Use of weakly anionic copolymers as dispersing and/or grinding aid agent of an aqueous suspension of mineral materials

ABSTRACT

The invention relates to the use of a slightly anionic and water-soluble copolymer, as a dispersing agent and/or an agent for assisting the grinding of pigments and/or mineral fillers in aqueous suspension giving on the one hand a low Zeta potential to the aqueous suspensions of the said fillers and/or pigments and on the other hand affording an electro-steric stabilisation of the said suspensions. 
     The invention also relates to the said aqueous suspensions of mineral pigments and/or fillers and their uses in the fields of paper, such as the manufacture or coating of paper, and drilling muds used for petroleum prospecting or extraction. 
     The invention also relates to the use of the said dispersing agents and/or agent for assisting the grinding in the field of paints and plastic materials such as thermoplastic or thermosetting resins.

The present invention relates to the technical sector of mineralfillers, notably for papermaking applications, and their appropriateprocessing in order to improve either the method of manufacturing thepaper sheet, or its properties.

The invention firstly relates to the use of a slightly anionic andwater-soluble copolymer as a dispersing agent and/or an aid to thegrinding of mineral pigments and/or fillers in aqueous suspension givingon the one hand a low Zeta potential to the aqueous suspensions of thesaid fillers and/or pigments and on the other hand affordingelectro-steric stabilisation of the said suspensions.

The invention also relates to the said slightly anionic water-solubleagent, dispersing agent and/or aid to the grinding of mineral pigmentsand/or fillers in aqueous suspension giving on the one hand a low Zetapotential to the aqueous suspensions of the said fillers and/or pigmentsand on the other hand affording electro-steric stabilisation of the saidsuspensions.

The invention also relates to the said aqueous suspensions of mineralpigments and/or fillers and the uses thereof notably in the fields ofpaper, such as amongst other things the manufacture or coating of thepaper, with the obtaining in particular of equal or better propertiesfor the sheet, and notably opacity, gloss or printability, or notably inthe field of drilling muds used in prospecting for oil or in oilextraction. The invention also concerns the use of the said slightlyanionic water-soluble dispersing agent and/or aid to the grinding in thefields of paints or plastic materials such as thermoplastic orthermosetting resins. Then, the invention relates to the manufacturedpapers and/or coated papers with the use of the said aqueous suspensionsof mineral pigments and/or fillers as well as relates to the drillingmuds containing the said aqueous suspensions of mineral pigments and/orfillers.

This is because, in the manufacture of paper, it is becoming more andmore usual to replace some of the cellulose fibres, which are expensive,with mineral fillers and/or pigments, which are less expensive, in orderto reduce the cost of the paper whilst improving, for example, itsopacity, its whiteness or its properties of printability.

The mineral fillers and/or pigments such as, for example, natural orsynthetic calcium carbonate, dolomites, magnesium hydroxide, kaolin,talc, gypsum, titanium oxide or aluminium hydroxide are normallyincorporated in the sheet of paper during its formation on the wire.

This is achieved by incorporating the mineral filler and/or pigment,either in powder form or in aqueous suspension, in the papermaking pulpin such a way that the pulp is drained onto the wire and the particlesof mineral fillers and/or pigments in suspension are retained in thefibrous sheet obtained. Since this retention is not complete, this leadsthe papermaker to use chemical additives and the manufacturers offillers to use surface treatment agents for these mineral materials.

Likewise, when the sheet of paper is treated by coating, the papermakeruses, in his formulation, mineral materials generally put in suspension,either by the papermaker himself or by the manufacturer, using anionicadditives such as for example polyacrylates or polyphosphates or othersor using cationic additives such as for example cationised polyacrylatesor polymethacrylates such as quaternary dimethylaminoethyl methacrylatesor melamine-formaldehyde resins, epichlorhydrine resins, dicyandiamideresins or others.

Thus the skilled man in the art knows agents assisting grinding orwater-soluble dispersing agents (FR 2 488 814, FR 2 603 042, EP 0 100947, EP 0 100 948, EP 0 129 329, EP 0 542 643, EP 0 542 644) consistingof polymers and/or copolymers of the anionic type for producing aqueoussuspensions of mineral pigments and/or fillers. However, these have thedrawback of requiring the addition of cationic compounds during theprocess of manufacturing the sheet of paper when they are used in thesesheet manufacturing operations, and result in coated papers with anopacity which does not meet the opacity required by the final use whenthey are used in paper coating operations.

Moreover, the skilled man in the art knows agents for assisting grindingor water-soluble dispersing agents (EP 0 281 134, EP 0 307 795)consisting of polymers and/or copolymers of the cationic type forproducing aqueous suspensions of mineral pigments and/or fillers whichpresent the major risk of incompatibility with any anionic mediumpresent in the papermaking formulations, which may go as far as thecaking of the medium, thus blocking production entirely.

Another solution is known to the skilled man in the art for arriving ataqueous suspensions of mineral pigments and/or fillers which are stableover time and have a high concentration of dry matter at the same timeas a fine particle size.

This solution (WO 91/09067) consists in using amphoteric water-solublecopolymers as a weakly anionic water-soluble dispersing agent and/or aidto the grinding of pigments and/or mineral fillers. However, suchcopolymers have the drawback of being sensitive to the pH and ionicstrength of the medium and also being easily hydrolysable.

Thus the skilled man in the art is confronted with the problem ofobtaining aqueous suspensions of mineral fillers and/or pigments whichare refined, stable over time, with a moderate to high concentration ofmineral material, which do not present any risk of incompatibility inpapermaking formulations, only slightly sensitive to the pH and ionicstrength of the media used in papermaking formulations and to theproblem of obtaining suspensions making it possible to arrive at sheetproperties meeting the criteria of the final user, a problem which noneof the solutions available to him completely resolve.

Bearing in mind the aforementioned drawbacks concerning anionic orcationic aqueous suspensions or aqueous suspensions obtained by means ofamphoteric agents, the Applicant unexpectedly found that the presence inthe copolymer of at least one monomer of formula (I)

in which

-   -   m and p represent a number of alkylene oxide units less than or        equal to 150,    -   n represents a number of ethylene oxide units less than or equal        to 150,    -   q represents a number at least equal to 1 and such that        5≦(m+n+p)q≦150

R₁ is hydrogen or the methyl or ethyl radical

R₂ is hydrogen or the methyl or ethyl radical

R represents the polymerisable unsaturated radical, belonging to thegroup of acrylic, methacrylic, maleic, itaconic, crotonic orvinylphthalic esters and unsaturated urethanes such as for exampleacrylurethane, methacrylurethane, α-α′ dimethylisopropenylbenzylurethane or allylurethane, and to the group of allyl or vinylethers or to the group of ethylenlcally unsaturated amides,

R′ represents a hydrocarbon radical having 1 to 5 carbon atoms

made possible the development of weakly anionic water-soluble copolymersallowing electro-steric stabilisation thus resulting in the obtaining ofaqueous suspensions of mineral pigments and/or fillers resolving theproblems set out above, that is to say resulting, notably, in theobtaining of aqueous suspensions of mineral pigments and/or fillers witha moderate to high mineral matter content, stable over time, withoutsedimentation, only slightly sensitive to the pH and ionic strength ofthe media used in the papermaking or petroleum formulations, and havinga low Zeta potential.

Thus the prior art essentially describes dispersing agents and/orgrinding aid agents which are anionic, cationic or amphoteric or weaklyanionic and water-soluble.

In fact European patent application EP 0 870 784 describes slightlyanionic agents, but these agents give aqueous suspensions with a highZeta potential and do not resolve the problem posed for the final user.

Thus, according to the invention, the dispersing agent and/or grindingaid agent is distinguished from the prior art in that it is composed of

a) at least one anionic monomer with a monocarboxylic function

b) possibly at least one anionic monomer with a dicarboxylic function orwith a sulphonic or phosphoric or phosphonic function or a mixturethereof

c) at least one non-ionic monomer, the non-ionic monomer consisting ofat least one monomer of formula (I):

in which

-   -   m and p represent a number of alkylene oxide units less than or        equal to 150,    -   n represents a number of ethylene oxide units less than or equal        to 150,    -   q represents a number at least equal to 1 and such that        5≦(m+n+p)q≦150

R₁ is hydrogen or the methyl or ethyl radical

R₂ is hydrogen or the methyl or ethyl radical

R represents the polymerisable unsaturated radical, belonging to thegroup of acrylic, methacrylic, maleic, itaconic, crotonic orvinylphthalic esters and unsaturated urethanes such as for exampleacrylurethane, methacrylurethane, α-α′ dimethylisopropenylbenzylurethane or allylurethane, and to the group of allyl or vinylethers or to the group of ethylenically unsaturated amides,

R′ represents a hydrocarbon radical having 1 to 5 carbon atoms

d) possibly a monomer of the acrylamide or methacrylamide type orderivatives thereof and mixtures thereof or one or more nonwater-soluble monomers such as alkyl acrylates or methacrylates, vinylcompounds such as vinyl acetate, vinylpyrrolidone, styrene,alphamethylstyrene and derivatives thereof, and

e) possibly at least one monomer having at least two unsaturatedethylenic chains referred to in the remainder of the application asacross-linking monomer

giving the properties of low Zeta potential and electro-steric stabilityto the suspensions.

These aims are achieved by means of the use, as a dispersing agentand/or a grinding aid agent, of a copolymer consisting of:

a) at least one anionic monomer with an unsaturated ethylenic chain andwith a monocarboxylic function

b) possibly at least one anionic monomer with an unsaturated ethylenicchain and a dicarboxylic or sulphonic or phosphoric or phosphonicfunction or a mixture thereof

c) at least one non-ionic monomer of formula (I) and

d) possibly a monomer of the acrylamide or methacrylamide type orderivatives thereof and mixtures thereof or one or more nonwater-soluble monomers with unsaturated ethylenic chains such as alkylacrylates or methacrylates, vinyl compounds such as vinyl acetate,vinylpyrrolidone, styrene, alphamethylstyrene and derivatives thereof,

e) possibly at least one cross-linking monomer

the total of constituents a), b), c), d) and e) being equal to 100%,with moreover the obligatory presence of a monomer of type a) in orderto be able to ensure the dispersion of the mineral materials with a highand medium concentration of dry matter and the obligatory presence of amonomer of type c) in combination with the monomer of type a) in orderto ensure the electro-steric stabilisation of the aqueous suspensions ofmineral materials with a high and medium concentration of dry matter.

The use according to the invention of a weakly anionic and water-solublecopolymer as a dispersing agent and/or a grinding aid agent for mineralpigments and/or fillers in aqueous suspension is characterised in thatthe said copolymer consists of:

a) at least one anionic monomer with an unsaturated ethylenic chain anda monocarboxylic function chosen from amongst the monomers with anunsaturated ethylenic chain and a monocarboxylic function such asacrylic or methacrylic acid or diacid hemiesters such as the C₁ to C₄monoesters of maleic or itaconic acids, or mixtures thereof,

b) possibly at least one anionic monomer with an unsaturated ethylenicchain and a dicarboxylic or sulphonic or phosphoric or phosphonicfunction or a mixture thereof chosen from amongst monomers with anunsaturated ethylenic chain and a dicarboxylic function such ascrotonic, isocrotonic, cinnamic, itaconic, maleic or citraconic acid orcarboxylic acid anhydrides, such as maleic anhydride, or chosen fromamongst monomers with an unsaturated ethylenic chain and a sulphonicfunction such as acrylamido-methylpropane sulphonic acid, sodiummethallylsulphonate, vinyl sulphonic acid and styrene sulphonic acid orchosen from amongst the monomers with an unsaturated ethylenic chain anda phosphoric function such as vinyl phosphoric acid, ethylene glycolmethacrylate phosphate, propylene glycol methacrylate phosphate,ethylene glycol acrylate phosphate, propylene glycol acrylate phosphateand their ethoxylates or chosen from amongst the monomers with anunsaturated ethylenic chain and a phosphonic function such as phosphonicvinyl acid, or mixtures thereof

c) at least one non-ionic monomer with an

unsaturated ethylenic chain of formula (I):

in which

-   -   m and p represent a number of alkylene oxide units less than or        equal to 150,    -   n represents a number of ethylene oxide units less than or equal        to 150,    -   q represents a number at least equal to 1 and such that        5≦(m+n+p)q≦150

R₁ is hydrogen or the methyl or ethyl radical

R₂ is hydrogen or the methyl or ethyl radical

R represents the polymerisable unsaturated radical, belonging to thegroup of acrylic, methacrylic, maleic, itaconic, crotonic orvinylphthalic esters and unsaturated urethanes such as for exampleacrylurethane, methacrylurethane, α-α′ dimethylisopropenylbenzylurethane or allylurethane, and to the group of allyl or vinylethers or to the group of ethylenically unsaturated amides,

R′ represents a hydrocarbon radical having 1 to 5 carbon atoms

d) possibly a monomer of the acrylamide or methacrylamide type orderivatives thereof and mixtures thereof or one or more nonwater-soluble monomers such as alkyl acrylates or methacrylates, vinylcompounds such as vinyl acetate, vinylpyrrolidone, styrene,alphamethylstyrene and derivatives thereof, and

e) possibly at least one cross-linking monomer chosen non-limitativelyfrom the group consisting of ethylene glycol dimethacrylate,trimethylolpropanetriacrylate, allyl acrylate, allyl maleates,methylenebisacrylamide, methylenebismethacrylamide, tetrallyloxyethane,the triallylcyanurates, and the allyl ethers obtained from polyols suchas pentaerythritol, sorbitol, sucrose and others,

the total of constituents a), b), c), d) and e) being equal to 100%

and in that the said copolymer has a specific viscosity of no more than10, preferably no more than 5 and highly preferentially no more than 2.

More particularly the use of the aforementioned copolymer ischaracterised in that the said copolymer consists, expressed by weight,of:

a) 2% to 85% and even more particularly 2% to 80% of at least oneanionic monomer with an unsaturated ethylenic chain and a monocarboxylicfunction chosen from amongst the monomers with an unsaturated ethylenicchain and a monocarboxylic function such as acrylic or methacrylic acidor the hemiesters of diacids such as the C₁ to C₄ monoesters of maleicor itaconic acids, or mixtures thereof,

b) from 0% to 80% and even more particularly from 0% to 50% and veryparticularly from 0% to 20% of at least one anionic monomer with anunsaturated ethylenic chain and a dicarboxylic or sulphonic orphosphoric or phosphonic function or a mixture thereof chosen fromamongst monomers with an unsaturated ethylenic chain and a dicarboxylicfunction such as crotonic, isocrotonic, cinnamic, itaconic, maleic orcitraconic acid or carboxylic acid anhydrides, such as maleic anhydride,or chosen from amongst monomers with an unsaturated ethylenic chain anda sulphonic function such as acrylamido-methyl-propane sulphonic acid,sodium methallylsulphonate, vinyl sulphonic acid and styrene sulphonicacid or chosen from amongst the monomers with an unsaturated ethylenicchain and a phosphoric function such as vinyl phosphoric acid, ethyleneglycol methacrylate phosphate, propylene glycol methacrylate phosphate,ethylene glycol acrylate phosphate, propylene glycol acrylate phosphateand their ethoxylates or chosen from amongst the monomers with anunsaturated ethylenic chain and a phosphonic function such as phosphonicvinyl acid, or mixtures thereof

c) from 20% to 95% of at least one monomer with an unsaturated ethylenicchain of formula (I):

in which

-   -   m and p represent a number of alkylene oxide units less than or        equal to 150,    -   n represents a number of ethylene oxide units less than or equal        to 150,    -   q represents a number at least equal to 1 and such that        5≦(m+n+p)q≦150

R₁ is hydrogen or the methyl or ethyl radical

R₂ is hydrogen or the methyl or ethyl radical

R represents the polymerisable unsaturated radical, belonging to thegroup of acrylic, methacrylic, maleic, itaconic, crotonic orvinylphthalic esters and unsaturated urethanes such as for exampleacrylurethane, methacrylurethane, α-α′ dimethylisopropenylbenzylurethane or allylurethane, and to the group of allyl or vinylethers or to the group of ethylenically unsaturated amides,

R′ represents a hydrocarbon radical having 1 to 5 carbon atoms

d) from 0% to 50% of a monomer of the acrylamide or methacrylamide typeor derivatives thereof and mixtures thereof or one or more nonwater-soluble monomers such as alkyl acrylates or methacrylates, vinylcompounds such as vinyl acetate, vinylpyrrolidone, styrene,alphamethylstyrene and derivatives thereof, and

e) from 0% to 3% of at least one cross-linking monomer chosennon-limitatively from the group consisting of ethylene glycoldimethacrylate, trimethylolpropanetriacrylate, allyl acrylate, allylmaleates, methylenebisacrylamide, methylenebismethacrylamide,tetrallyloxyethane, the triallylcyanurates, or the allyl ethers obtainedfrom polyols such as pentaerythritol, sorbitol, sucrose or others,

the total of constituents a), b), c), d) and e) being equal to 100%

and in that the said copolymer has a specific viscosity of no more than10, preferably no more than 5 and highly preferentially no more than 2.

Even more preferentially, the use of the copolymer is characterised inthat

a) the anionic monomer with unsaturated ethylenic chains andmonocarboxylic function is preferably chosen from amongst the monomerswith an unsaturated ethylenic chain and a monocarboxylic function suchas acrylic or methacrylic acid,

b) the anionic monomer with an unsaturated ethylenic chain and adicarboxylic or sulphonic or phosphoric or phosphonic function or amixture thereof is preferably chosen from amongst the monomers with anunsaturated ethylenic chain and a dicarboxylic function such as diacidsincluding itaconic or maleic acid or chosen from amongst the monomerswith an unsaturated ethylenic chain and a sulphonic function such asacrylamido-methyl-propanesulphonic acid, sodium methallylsulphonate,vinyl sulphonic acid and styrene sulphonic acid or chosen from amongstthe monomers with an unsaturated ethylenic chain and a phosphoricfunction such as ethylene glycol methacrylate phosphate, propyleneglycol methacrylate phosphate, ethylene glycol acrylate phosphate,propylene glycol acrylate phosphate and their ethoxylates or mixturesthereof

c) the non-ionic monomer with an unsaturated ethylenic chain of formula(I) is such that

R₁ represents hydrogen or the methyl or ethyl radical

R₂ represents hydrogen or the methyl or ethyl radical

R represents the polymerisable unsaturated radical, belonging to thegroup of acrylic, methacrylic, maleic, itaconic, crotonic orvinylphthalic esters as well as unsaturated urethanes such as forexample acrylurethane, methacrylurethane, α-α′ dimethylisopropenylbenzylurethane, allylurethane, and to the group of allyl or vinyl ethersor to the group of ethylenically unsaturated amides,

R′ represents a hydrocarbon radical having 1 to 5 carbon atoms

d) the monomer of the acrylamide or methacrylamide type or derivativesthereof is chosen from amongst acrylamide or methacrylamide, and the nonwater-soluble monomer is chosen from amongst ethyl acrylate or styrene

e) the cross-linking agent is chosen from amongst the group consistingof ethylene glycol dimethacrylate, trimethylolpropanetriacrylate, allylacrylate, the allyl maleates, methylenebisacrylamide,methylenebismethacrylamide, tetrallyloxyethane, the triallylcyanurates,the allyl ethers obtained from polyols such as pentaerythritol,sorbitol, sucrose or others.

The copolymer used according to the invention is obtained by knownmethods of radical copolymerisation in solution, in direct or reverseemulsion, in suspension or precipitation in suitable solvents, in thepresence of catalytic systems and known transfer agents.

This copolymer obtained in acid form and possibly distilled can also bepartially or completely neutralised by one or more neutralisation agentshaving a monovalent neutralising function or a polyvalent neutralisingfunction such as for example, for the monovalent function, those chosenfrom the group consisting of alkali cations, in particular sodium,potassium, lithium, ammonium or the aliphatic and/or cyclic primary,secondary or tertiary amines such as for example stearylamine, theethanolamines (mono-, di, triethanolamine), mono and diethylamine,cyclohexylamine, methylcyclohexylamine or, for the polyvalent function,those chosen from the group consisting of alkaline-earth divalentcations, in particular magnesium and calcium, or zinc, also consistingof trivalent cations, in particular aluminium, or certain cations with ahigher valency.

Each neutralisation agent then acts according to the degrees ofneutralisation peculiar to each valency function.

According to another variant, the copolymer resulting from thecopolymerisation reaction can, possibly before or after the complete orpartial neutralisation reaction, be treated and separated into severalphases, according to static or dynamic methods known to experts, bymeans of one or more polar solvents belonging notably to the groupconsisting of water, methanol, ethanol, propanol, isopropanol, thebutanols, acetone, tetrahydrofuran or mixtures thereof.

One of the phases then corresponds to the copolymer used according tothe invention as a dispersing agent and/or a grinding aid agent formineral materials in aqueous suspension.

The specific viscosity of the copolymer is symbolised by the letter ηand is determined as follows:

A solution of polymerisate is taken so as to obtain a solutioncorresponding to 2.5 g of dry polymer neutralised with soda and to 50 mlof a solution of bipermuted water. Then, with a capillary viscometerwith a Baume constant of 0.000105 placed in a bath thermostaticallycontrolled at 25° C., a measurement is made of the run-out time for agiven volume of the aforementioned solution containing the copolymer,and the run-out time for the same volume of the solution of bipermutedwater without the said copolymer. It is then possible to define thespecific viscosity η by means of the following equation:$\eta = \frac{\begin{matrix}\left( {{run}\text{-}{out}\quad{time}\quad{of}} \right. \\\left. {{the}\quad{polymer}\quad{solution}} \right)\end{matrix} - \begin{matrix}\left( {{run}\text{-}{out}\quad{time}\quad{of}\quad{the}} \right. \\\left. {{permuted}\quad{water}\quad{solution}} \right)\end{matrix}}{\left( {{run}\text{-}{out}\quad{time}\quad{of}\quad{the}\quad{permuted}\quad{water}\quad{solution}} \right)}$

The capillary tube is generally chosen so that the run-out time of thepermuted water solution with no copolymer is approximately 60 to 100seconds, thus giving specific viscosity measurements with very goodprecision.

The invention also relates to the said water-soluble, weakly anionicagent, dispersing agent and/or grinding aid agent for pigments and/ormineral fillers in aqueous suspension giving on the one hand a low Zetapotential to the aqueous suspensions of the said fillers and/or pigmentsand on the other hand affording an electro-steric stabilisation of thesaid suspensions. This agent is characterised in that it is thepreviously described copolymer.

The aqueous suspensions of fillers and/or pigments according to theinvention are characterised in that they contain the said agent and moreparticularly in that they contain from 0.05% to 5% by dry weight of thesaid agent with respect to the total dry weight of the fillers and/orpigments, and even more particularly 0.3% to 1.0% by dry weight of thesaid agent with respect to the total dry weight of the fillers and/orpigments.

They are also characterised in that the filler and/or pigment is chosenfrom amongst natural calcium carbonate such as notably calcite, chalk ormarble, synthetic calcium carbonate named precipitated calciumcarbonate, dolomites, magnesium hydroxide, kaolin, talc, gypsum,titanium oxide, or aluminium hydroxide or any other filler and/orpigment normally used in the papermaking or petroleum field.

Finally, they are characterised in that they are only slightly sensitiveto the pH and ionic strength of the media and in that they have a lowZeta potential, that is to say a Zeta potential of between 0 and −30 mVand preferentially between 0 and −20 mV.

The papers manufactured and/or coated according to the invention arecharacterised in that they contain the said aqueous suspensions offillers and/or pigments according to the invention.

The drilling muds according to the invention are characterised in thatthey contain the said aqueous suspensions of fillers and/or pigmentsaccording to the invention.

In practice, the dispersing operation, also referred to as the operationof dispersing the mineral filler to be dispersed, can be effected in twodifferent ways.

One of the ways consists in effecting, under agitation, the preparationof a suspension of mineral filler and/or pigment by introducing all orpart of the dispersing agent according to the invention into the aqueousphase, and then the mineral material, so as to obtain an aqueoussuspension with a moderate to high mineral material content, stable overtime, without sedimentation, only slightly sensitive to the pH and ionicstrength of the media used in the papermaking formulations, and having alow Zeta potential, that is to say a Zeta potential of between 0 and −30mV and preferentially between 0 and −20 mV.

Another way consists in preparing the suspension of mineral fillerand/or pigment by introducing into the mineral filler and/or pigmentcake all the quantity of dispersing agent to be tested so as to obtainan aqueous suspension with a moderate to high mineral material content,stable over time, without sedimentation, only slightly sensitive to thepH and ionic strength of the media used in the papermaking formulations,and having a low Zeta potential, that is to say a Zeta potential ofbetween 0 and −30 mV and preferentially between 0 and −20 mV.

This dispersing operation can follow on from the grinding operationdescribed below or can be implemented completely independently.

Thus, in practice, the operation of grinding the mineral material to berefined consists in grinding the mineral substance with a grindingsubstance of very fine particles in an aqueous medium containing thegrinding aid agent.

To the aqueous suspension of the mineral substance to be ground, thegrinding substance with a particle size advantageously between 0.20 and4 millimetres is added. The grinding substance is generally in the formof particles of materials which are as diverse as silicon oxide,aluminium oxide, zirconium oxide or mixtures thereof, and syntheticresins with high hardness, steels, or others. An example of thecomposition of such grinding substances is given by the patent FR 2 303681, which describes the grinding element formed by 30% to 70% by weightzirconium oxide, 0.1% to 5% aluminium oxide and 5% to 20% silicon oxide.

The grinding substance is preferably added to the suspension in aquantity such that the ratio by weight between this grinding materialand the mineral substance to be ground is at least 2/1, this ratiopreferably being between the limits 3/1 and 5/1.

The mixture of the suspension and grinding substance is then subjectedto the mechanical action of stirring, such as the one which occurs in aconventional grinder with microelements.

The time required for achieving the required fineness of the mineralsubstance after grinding varies according to the nature and quantity ofthe mineral substances to be ground, and according to the stirring modeused and the temperature of the medium during the grinding operation.

The aqueous suspensions thus obtained can be used in the field of paperin mass filling or in coating with a low Zeta potential.

During the manufacture of the sheet of paper, that is to say duringtheir use as a mass filler, these suspensions can be used with thecoating broke.

They can also be used in the field of drilling muds such as for examplesoft bentonitic muds, saturated salt muds and sea-water muds.

The scope and interest of the invention will be perceived more clearlyby means of the following examples, which are not limitative.

EXAMPLE 1

This example relates to the preparation of a calcium carbonatesuspension by simple dispersion and the revealing of the propertiesafforded by the presence of at least one monomer of formula (I) in thenon-ionic monomer.

To this end, for each of the following tests, carried out using a marblefiltration cake in which 73% of the particles have a diameter less than1 micrometre determined by measurement using the Sedigraph™ 5100 fromMicromeritics, the aqueous suspension of marble is prepared by theintroduction, into the cake, of the necessary quantity by dry weight ofdispersion agent to be tested with respect to the dry weight of the saidcake to be put in suspension in order to obtain an aqueous suspension ofcalcium carbonate with a dry matter concentration of 61%.

After 20 minutes stirring, a sample of the suspension of calciumcarbonate obtained is recovered in a flask and the Brookfield™ viscosityis measured by means of a Brookfield™ type RVT viscometer, at atemperature of 25° C. and a speed of rotation of 10 and 100 revolutionsper minute with the appropriate spindle.

After a time of 8 days in the flask, the Brookfield™ viscosity of thesuspension is measured by introducing, into the unstirred flask, theappropriate spindle of the Brookfield™ type RVT viscometer, at atemperature of 25° C. and a speed of rotation of 10 revolutions and 100revolutions per minute (BS viscosity Brookfield™ viscosity beforestirring).

The same Brookfield™ viscosity measurements are also made once the flaskhas been stirred and constitute the results of Brookfield™ viscosityafter stirring (AS viscosity).

For measuring the Zeta potential, a sample of the suspension of calciumcarbonate obtained is also recovered, after the 20 minutes of stirring,and a few drops of this is dispersed in a sufficient quantity of serumobtained by mechanical filtration of the said suspension in order toobtain a colloidal suspension which is scarcely cloudy.

This suspension is introduced into the measuring cell of the ZetamasterS Zetameter from Malvern, which directly displays the value of the Zetapotential in mV.

These different measurements were carried out for the following tests.

Test N^(o) 1:

This test, illustrating the prior art, used 0.7% by dry weight of asodium polyacrylate with a specific viscosity of 4.80.

Test N^(o) 2:

This test, illustrating the prior art, used 0.7% by dry weight of anacrylic acid-maleic anhydride copolymer completely neutralised with sodaand with a specific viscosity of 1.38.

Test N^(o) 3:

This test, illustrating a field outside the invention, used 0.7% by dryweight of a homopolymer, with a specific viscosity of 0.91 and whosesingle monomer is a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 4:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.28and consisting of:

a) 8.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 5.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 82.0% by weight of a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

d) 4.5% by weight ethyl acrylate

with (m+n+p)q=113.

Test N^(o) 5:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.78and consisting of:

a) 8.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 5.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 75.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

d) 11.5% by weight ethyl acrylate

with (m+n+p)q=40.

Test N^(o) 6:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.51and consisting of:

a) 8.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 5.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 71.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

d) 15.5% by weight ethyl acrylate

with (m+n+p)q=25.

Test N^(o) 7:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.51and consisting of:

a) 8.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 5.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 67.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

d) 19.5% by weight ethyl acrylate

with (m+n+p)q=17.

Test N^(o) 8:

This test, illustrating the invention, used 0.6% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.56and consisting of:

a) 2.0% by weight methacrylic acid as an anionic monomer with amonocarboxylic function

b) 13.0% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 85.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=113.

Test N^(o) 9:

This test, illustrating the invention, used 0.6% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.97and consisting of:

a) 3.2% by weight methacrylic acid as an anionic monomer with amonocarboxylic function

b) 13.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 83.3% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 10:

This test, illustrating the invention, used 0.6% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.96and consisting of:

a) 8.5% by weight methacrylic acid as an anionic monomer with amonocarboxylic function

b) 13.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 78.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=17.

Test N^(o) 11:

This test, illustrating the invention, used 0.6% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.07and consisting of:

a) 17.0% by weight methacrylic acid as an anionic monomer with amonocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 12:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.04and consisting of:

a) 3.2% by weight methacrylic acid and 13.0% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 8.0% by weight acrylamido methyl propanesulphonic acid as an anionicmonomer with a sulphonic function

c) 75.8% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 13:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.47and consisting of:

a) 3.3% by weigh methacrylic acid and 13.0% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 5.0% by weight itaconic acid as an anionic monomer with adicarboxylic function

c) 78.7% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 14:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.38and consisting of:

a) 0.8% by weight methacrylic acid and 79.3% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 19.9% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 15:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.38and consisting of:

a) 0.4% by weight methacrylic acid and 79.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 20.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=113.

Test N^(o) 16:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.28and consisting of:

a) 35.0% by weight acrylic acid as anionic monomers with amonocarboxylic function

b) 20.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

c) 45.0% by weight acrylamide

with (m+n+p)q=17.

Test N^(o) 17:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.03and consisting of:

a) 35.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 20.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

c) 45.0% by weight acrylamide

with (m+n+p)q=45.

Test N^(o) 18:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.65and consisting of:

a) 15.0% by weight methacrylic acid and 12.0% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 73.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=8.

Test N^(o) 19:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.38and consisting of:

a) 3.4% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 82.1% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

c) 1.0% by weight EDMA as a cross-linking monomer

with (m+n+p)q=45.

Test N^(o) 20:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.16and consisting of:

a) 3.9% by weight methacrylic acid and 1.1% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 95.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 21:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.07and consisting of:

a) 0.8% by weight methacrylic acid and 79.2% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 20.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 22:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.28and consisting of:

a) 1.7% by weight methacrylic acid and 13.2% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 85.6% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the propyl radical

with (m+n+p)q=64.

Test N^(o) 22 bis:

This test, illustrating the invention, used 0.7% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.68and consisting of:

a) 45% by weight acrylic acid as anionic monomers with a monocarboxylicfunction

b) 35% by weight acrylamido methyl propanesulphonic acid as an anionicmonomer with a sulphonic function

c) 20% by weight of 2 monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=17.

All the experimental results are set out in the following Tables 1a to1d.

TABLE 1a BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 0 100 0 100 0 100 POTENTIALN° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/min rev/minrev/min rev/min (mV) Prior art  1 100% AA 4.80 1000 280 6000 1500  1000300 −50.6 Prior art  2 70% AA 30% Maleic anhydride 1.38  180 110 2000500  400 150 −50.7 Field  3 100% methoxy PEGM 2000 0.91 2400 1600 Excessively high non-measurable viscosity outside invention Invention  48.0% AA 1.28 4680 830 2000 600 1000 440 −20.2 5.5% EGMP 82.0% methoxyPEG MU 5000 4.5% EA Invention  5 8.0% AA 0.78 3960 1044  7600 960 4000840 −16.8 5.5% EGMP 75.0% methoxy PEG MU 1800 11.5% EA Invention  6 8.0%AA 5.5% EGMP 71.0% methoxy PEG MU 1100 0.51 1860 455 3200 1140  1450 520−20.7 15.5% EA AA = Acrylic acid. EA = Ethyl acrylate. Methoxy PEG MU1100 = Methoxy polyethylene glycol methacrylurethane with molecularweight 1100. Methoxy PEGM 2000 = Methoxy polyethylene glycolmethacrylate with molecular weight 2000. EGMP = Ethylene glycolmethacrylate phosphate. Methoxy PEG MU 1800 = Methoxy polyethyleneglycol methacrylurethane with molecular weight 1800. AMPS =Acrylamido-methyl-propane-sulphonic acid. Methoxy PEG MU 5000 = Methoxypolyethylene glycol methacrylurethane with molecular weight 5000.

TABLE 1b BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/minrev/min rev/min rev/min (mV) Invention  7 8.0% AA 0.51 7600 968 93001500  7300 1540  −23.3 5.5% EGMP 67.0% methoxy PEG MU 750 19.5% EAInvention  8 2.0% MAA 1.56 1800 500 3200 800 1300 450 −7.3 13.0% EGMP85.0% methoxy PEGM 5000 Invention  9 3.2% MAA 0.97  750 330 3000 500 700 240 −12.6 13.5% EGMP 83.3% methoxy PEGM 2000 Invention 10 8.5% MAA0.96 1200 280 5600 920 1700 370 −25.2 13.5% EGMP 78.0% methoxy PEGM 750Invention 11 17.0% MAA 1.07 1700 550 1360 750 1980 650 −16.5 83.0%methoxy PEGM 2000 Invention 12 3.2% MAA 1.04 2800 790 3000 900 2100 530−18.7 13.0% AA 8.0% AMPS 75.8% methoxy PEGM 2000 AA = Acrylic acid. EA =Ethyl acrylate. MAA = Methacrylic acid. Methoxy PEG MU 750 = Methoxypolyethylene glycol methacrylurethane with molecular weight 750. MethoxyPEGM 2000 = Methoxy polyethylene glycol with molecular weight 2000. EGMP= Ethylene glycol methacrylate phosphate. AMPS =Acrylamido-methyl-propane-sulphonic acid. Methoxy PEGM 5000 = Methoxypolyethylene glycol methacrylate with molecular weight 5000.

TABLE 1c BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/minrev/min rev/min rev/min (mV) Invention 13 3.3% MMA 1.47 1100  330 60001000 1900 570 −10.9 13.0% AA 5.0% ITCA 78.7% methoxy PEGM 2000 Invention14 0.8% MMA 1.38 7000 1000 8000 1100 6000 810 −27.5 79.3% AA 19.9%methoxy PEGM 2000 Invention 15 0.4% MMA 1.38 6800  900 8000 1080 5600800 −24.5 79.6% AA 20.0% methoxy PEGM 5000 Invention 16 35.0% AA 1.287400 1020 9100 1340 7240 1040  −29.8 20.0% methoxy PEG MU 750 45.0%Acrylamide Invention 17 35.0% AA 1.03 8000 1060 11800  1630 7500 1080 −25.7 20.0% methoxy PEGM 2000 45.0% Acrylamide Invention 18 15.0% MMA1.65 2200  650 7000 1150 1600 380 −29.8 12.0% AA 73.0% methoxy PEGM 350AA = Acrylic acid. MAA = Methacrylic acid. Methoxy PEG MU 750 = Methoxypolyethylene glycol methacrylurethane with molecular weight 750. MethoxyPEGM 2000 = Methoxy polyethylene glycol methacrylurethane with molecularweight 2000. Methoxy PEGM 350 = Methoxy polyethylene glycol methacrylatewith molecular weight 350. ITCA = Itaconic acid. AMPS =Acrylamido-methyl-propane-sulphonic acid. Methoxy PEGM 5000 = Methoxypolyethylene glycol methacrylate with molecular weight 5000.

TABLE 1d BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/minrev/min rev/min rev/min (mV) Invention 19 3.4% MMA 1.38 3400  650 12000 2000 2100  520 −12.5 13.5% AA 82.1% methoxy PEGM 2000 1.0% EDMAInvention 20 3.9% MMA 1.16 9000 3600 11000  4250 5150 2000 −12.5 1.1% AA95.0% methoxy PEGM 2000 Invention 21 0.8% MMA 1.07 9400 1080 9000 12508050 1150 −20.3 79.2% AA 20.0% methoxy PEGM 2000 Invention 22 1.7% MMA1.28 11200  1440 12000  2100 9000 1200 −16.5 13.2% AA 85.6% propoxy PEGM2800 Invention 22 45% AA 0.68 3450  685 3880 1156 3100  653 −28 bis 35%AMPS 20% methoxy PEGM 750 AA = Acrylic acid. MAA = Methacrylic acid.Methoxy PEGM 2000 = Methoxy polyethylene glycol methacrylate withmolecular weight 2000. Propoxy PEGM 2800 = Propoxy polyethylene glycolmethacrylate with molecular weight 2800. Methoxy PEGM 750 = Methoxypolyethylene glycol methacrylate with molecular weight 750 AMPS =Acrylamido-methyl-propane-sulphonic acid

A reading of Tables 1a to 1d shows that the use of copolymer accordingto the invention containing, as a non-ionic monomer, at least onemonomer of formula (I) results in the obtaining of aqueous suspensionsof mineral pigments and/or fillers, according to the invention, with amoderate to high mineral material content, stable over time and having alow Zeta potential.

EXAMPLE 2

The purpose of this example is to illustrate different levels of use ofdispersing agent according to the invention.

To this end, with the same operating method and the same equipment as inexample 1, different levels of copolymer according to the invention aretested.

Test N^(o) 23:

This test, illustrating the invention, used 0.4% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.98and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 24:

This test, illustrating the invention, used 0.6% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.17and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=11.

Test N^(o) 25:

This test, illustrating the invention, used 1.0% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.86and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=17.

All the experimental results are set out in Table 2 below.

TABLE 2 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERQUANTITY INITIAL STIRRING STIRRING ZETA TEST OF AGENT 10 100 10 100 10100 POTENTIAL N° CONSTITUENT MONOMERS (% dry/dry) rev/min rev/minrev/min rev/min rev/min rev/min (mV) Invention 23 3.5% MMA 0.4 2000 4801800 660 1890 540 −20.8 13.5% AA 83.0% methoxy PEGM 2000 Invention 243.5% MMA 0.6 2600 540 3000 750 2500 510 −24.2 13.5% AA 83.0% methoxyPEGM 500 Invention 25 3.5% MMA 1.0 8000 1300  9000 1600  8500 1500 −25.9 13.5% AA 83.0% methoxy PEGM 750 AA = Acrylic acid. MAA =Methacrylic acid. Methoxy PEGM 750 = Methoxy polyethylene glycolmethacrylate with molecular weight 750. Methoxy PEGM 2000 = Methoxypolyethylene glycol methacrylate with molecular weight 2000. MethoxyPEGM 500 = Methoxy polyethylene glycol methacrylate with molecularweight 500.

A reading of Table 2 shows that the aqueous suspensions of mineralpigments and/or fillers, according to the invention, with a moderate tohigh mineral material content, stable over time and having a low Zetapotential, contain 0.05% to 5% by dry weight of the agent according tothe invention compared with the total dry weight of the fillers and/orpigments, and even more particularly 0.3% to 1.0% by dry weight of thesaid agent with respect to the total dry weight of the fillers and/orpigments.

EXAMPLE 3

The purpose of this example is to illustrate the different values of theproduct (m+n+p)q of the monomer with an unsaturated ethylenic non-ionicchain of formula (I) of the dispersing agent according to the invention.

For this purpose, with the same operating mode and the same equipment asin example 1, different copolymers according to the invention aretested.

Test N^(o) 26:

This test, illustrating the invention, used 0.4% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.19and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=17.

Test N^(o) 27:

This test, illustrating the invention, used 0.8% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 0.81and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=25.

Test N^(o) 28:

This test, illustrating the invention, used 0.4% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 1.05and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (T) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 29:

This test, illustrating the invention, used 0.4% by dry weight of apolymer fully neutralised with soda, with a specific viscosity of 2.57and consisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=113.

All the experimental results are set out in Table 3 below.

TABLE 3 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST 10 100 10 100 10 100 POTENTIAL N°CONSTITUENT MONOMERS (m + n + p)q rev/min rev/min rev/min rev/minrev/min rev/min (mV) Invention 26 3.5% MMA 17 4000 820 3200  980 4500930 −23.9 13.5% AA 83.0% methoxy PEGM 750 Invention 27 3.5% MMA 25 3200810 4000 1000 3500 940 −22.1 13.5% AA 83.0% methoxy PEGM 1100 Invention28 3.5% MMA 45 2000 470 3000  850 2230 590 −18.6 13.5% AA 83.0% methoxyPEGM 2000 Invention 29 3.5% MMA 113 4600 820 9000 1600 5000 1200  −6.713.5% AA 83.0% methoxy PEGM 5000 AA = Acrylic acid. MAA = Methacrylicacid. Methoxy PEGM 750 = Methoxy polyethyleneglycolmethacrylate withmolecular weight 750. Methoxy PEGM 2000 = Methoxypolyethyleneglycolmethacrylate with molecular weight 2000. Methoxy PEGM1100 = Methoxy polyethyleneglycolmethacrylate with molecular weight1100. Methoxy PEGM 5000 = Methoxy polyethyleneglycolmethacrylate withmolecular weight 5000.

A reading of Table 3 shows that the use of a copolymer according to theinvention containing, as a non-ionic monomer, at least one monomer offormula (I) with 5≦(m+n+p)q≦150 results in the obtaining of aqueoussuspensions of mineral pigments and/or fillers, according to theinvention, with a moderate to high mineral material content, stable overtime and having a low Zeta potential.

EXAMPLE 4

The purpose of this example is to illustrate different molecular weightsof the dispersing agent according to the invention.

For this purpose, with the same operating mode and the same equipment asin example 1, tests were carried out on different copolymers which allhad a different specific viscosity for the same composition by weight ofmonomer and the same form of neutralisation.

For tests 30 to 35, these were copolymers fully neutralised with sodaand consisting of

a) 3.2% by weight methacrylic acid as an anionic monomer with amonocarboxylic function

b) 13.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 83.3% by weight of a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

and having the following specific viscosities:

Test N^(o) 30:

The polymer used in this test, at 0.6% by dry weight with respect to thedry weight of marble, has a specific viscosity of 0.97 and illustratesthe invention.

Test N^(o) 31:

The polymer used in this test, at 0.6% by dry weight with respect to thedry weight of marble, has a specific viscosity of 1.57 and illustratesthe invention.

Test N^(o) 32:

The polymer used in this test, at 1.0% by dry weight with respect to thedry weight of marble, has a specific viscosity of 1.75 and illustratesthe invention.

Test N^(o) 33:

The polymer used in this test, at 0.8% by dry weight with respect to thedry weight of marble, has a specific viscosity of 3.72 and illustratesthe invention.

Test N^(o) 34:

The polymer used in this test, at 1.0% by dry weight with respect to thedry weight of marble, has a specific viscosity of 3.74 and illustratesthe invention.

Test N^(o) 35:

The polymer used in this test, at 1.0% by dry weight with respect to thedry weight of marble, has a specific viscosity of 5.08 and illustratesthe invention.

For tests 36 to 39, these are copolymers fully neutralised with soda andconsisting of

a) 8.0% by weight acrylic acid as an anionic monomer with amonocarboxylic function

b) 5.5% by weight ethylene glycol methacrylate phosphate as an anionicmonomer with a phosphoric function

c) 82.0% by weight of a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylurethane group    -   R′ represents the methyl radical

d) 4.5% by weight ethyl acrylate

with (m+n+p)q=113.

and having the following specific viscosities:

Test N^(o) 36:

The polymer used in this test, at 0.8% by dry weight with respect to thedry weight of marble, has a specific viscosity of 1.19 and illustratesthe invention.

Test N^(o) 37:

The polymer used in this test, at 0.8% by dry weight with respect to thedry weight of marble, has a specific viscosity of 1.31 and illustratesthe invention.

Test N^(o) 38:

The polymer used in this test, at 0.8% by dry weight with respect to thedry weight of marble, has a specific viscosity of 1.83 and illustratesthe invention.

Test N^(o) 39:

The polymer used in this test, at 0.8% by dry weight with respect to thedry weight of marble, has a specific viscosity of 2.04 and illustratesthe invention.

For tests 40 and 41, these are copolymers fully neutralised with sodaand consisting of

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)_(q 45).

and having the following specific viscosities:

Test N^(o) 40:

The polymer used in this test, at 0.4% by dry weight with respect to thedry weight of marble, has a specific viscosity of 0.98 and illustratesthe invention.

Test N^(o) 41:

The polymer used in this test, at 0.4% by dry weight with respect to thedry weight of marble, has a specific viscosity of 2.33 and illustratesthe invention.

All the Brookfield™ viscosity and Zeta potential experimental resultsmeasured with the same equipment and under the same operating conditionsas in Example 1 are set out in Tables 4a and 4b below.

TABLE 4a BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/minrev/min rev/min rev/min (mV) Invention 30 3.2% MMA 0.97  750  330 3000 500  700  240 −12.6 13.5% EGMP 83.3% methoxy PEGM 2000 Invention 313.2% MMA 1.57 7400  920 13000  1300 8400 1120 −15.7 13.5% EGMP 83.3%methoxy PEGM 2000 Invention 32 3.2% MMA 1.75 19000  2900 22000  320020000  3000 −16.8 13.5% EGMP 83.3% methoxy PEGM 2000 Invention 33 3.2%MMA 3.72 20000  2800 25000  3000 22000  2900 −16 13.5% EGMP 83.3%methoxy PEGM 2000 Invention 34 3.2% MMA 3.74 9000 1450 13000  195010000  1550 −15.7 13.5% EGMP 83.3% methoxy PEGM 2000 Invention 35 3.2%MMA 5.08 13000  2600 15000  2750 14000  2700 −18.6 13.5% EGMP 83.3%methoxy PEGM 2000 AA = Acrylic acid. MAA = Methacrylic acid. MethoxyPEGM 2000 = Methoxy polyethylene glycol with molecular weight 2000. EGMP= Ethylene glycol methacrylate phosphate. EA = Ethyl acrylate.

TABLE 4b BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST SPECIFIC 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS VISCOSITY rev/min rev/min rev/minrev/min rev/min rev/min (mV) Invention 36 8.0% AA 1.19 2200 780 50001700 3200 1140  −6.2 5.5% EGMP 82.0% methoxy PEG MU 5000 4.5% EAInvention 37 8.0% AA 1.31  950 430 4500  700  700 390 −5.7 5.5% EGMP82.0% methoxy PEG MU 5000 4.5% EA Invention 38 8.0% AA 1.83 6400 9707000 1100 1900 600 −8.6 5.5% EGMP 82.0% methoxy PEG MU 5000 4.5% EAInvention 39 8.0% AA 2.04 6800 1280  9000 1350 2200 920 −5.6 5.5% EGMP82.0% methoxy PEG MU 5000 4.5% EA Invention 40 3.5% MMA 0.98 2000 4801800  660 1890 540 −20.8 13.5% AA 83.0% methoxy PEGM 2000 Invention 413.5% MMA 2.33 6400 920 5000 1010 6900 1400  −15.2 13.5% AA 83.0% methoxyPEGM 2000 AA = Acrylic acid. MAA = Methacrylic acid. Methoxy PEGM 2000 =Methoxy polyethylene glycol with molecular weight 2000. EGMP = Ethyleneglycol methacrylate phosphate. Methoxy PEG MU 5000 = Methoxypolyethylene glycol methacrylurethane with molecular weight 5000. EA =Ethyl acrylate.

A reading of Tables 4a and 4b shows that the use of a copolymeraccording to the invention having a specific viscosity of no more than10, preferentially no more than 5 and highly preferentially no more than2, results in the obtaining of aqueous suspensions of mineral pigmentsand/or fillers, according to the invention, with a high mineral materialcontent, stable over time and having a low Zeta potential.

EXAMPLE 5

The purpose of this example is to illustrate different types and degreesof neutralisation of the dispersing agent according to the invention.

For this purpose, with the same operating mode and the same equipment asin example 1, tests were carried out, at 0.4% by dry weight with respectto the dry weight of marble, on the following different copolymers,which had different neutralisations for the same composition by weightof monomer and the same specific viscosity.

These were all copolymers with a specific viscosity of 1.05 andconsisting of:

a) 3.5% by weight methacrylic acid and 13.5% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which:

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

The different types and degrees of neutralisation are as follows:

Test N^(o) 42:

The polymer used in this test is fully neutralised with potash andillustrates the invention.

Test N^(o) 43:

The polymer used in this test is fully neutralised with ammoniumhydroxide and illustrates the invention.

Test N^(o) 44:

The polymer used in this test is totally acidic and illustrates theinvention.

Test N^(o) 45:

The polymer used in this test is fully neutralised with triethanolamineand illustrates the invention.

Test N^(o) 46:

The polymer used in this test is fully neutralised with lithiumhydroxide and illustrates the invention.

Test N^(o) 47:

The polymer used in this test is neutralised to the extent of 50% molarwith magnesium hydroxide and illustrates the invention.

Test N^(o) 48:

The polymer used in this test is fully neutralised with a mixturecomposed of 70% molar soda and 30% molar lime and illustrates theinvention.

Test No 49:

The polymer used in this test is fully neutralised with a mixturecomposed of 50% molar soda and 50% molar magnesium hydroxide andillustrates the invention.

All the Brookfield™ viscosity and Zeta potential experimental resultsmeasured with the same equipment and under the same operating conditionsas in Example 1 are set out in Tables 5a and 5b below.

TABLE 5a BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST NEUTRALI- 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS SATION rev/min rev/min rev/min rev/minrev/min rev/min (mV) Invention 42 3.5% MMA 100 K 1100 255 3000  700 1200290 −19.5 13.5% AA 83.0% methoxy PEGM 2000 Invention 43 3.5% MMA 100NH₄OH 6000 840 6000 1100 4500 790 −14.7 13.5% AA 83.0% methoxy PEGM 2000Invention 44 3.5% MMA 0 2200 490 5000 1000 2500 290 −10.1 13.5% AA 83.0%methoxy PEGM 2000 Invention 45 3.5% MMA 100 TEA 4500 700 4000  900 2900550 −14.8 13.5% AA 83.0% methoxy PEGM 2000 Invention 46 3.5% MMA 100 Li4100 670 8000 1050 7000 950 −20.3 13.5% AA 83.0% methoxy PEGM 2000Invention 47 3.5% MMA 50 Mg 1500 360 3500  650 1700 325 −8.8 13.5% AA83.0% methoxy PEGM 2000 AA = Acrylic acid. MAA = Methacrylic acid.Methoxy PEGM 2000 = Methoxy polyethylene glycol with molecular weight2000.

TABLE 5b BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST NEUTRALI- 10 100 10 100 10 100POTENTIAL N° CONSTITUENT MONOMERS SATION rev/min rev/min rev/min rev/minrev/min rev/min (mV) Invention 48 3.5% MMA 70 Na-30 Ca  4000 620 50001000 4000 720 −18.9 13.5% AA 83.0% methoxy PEGM 2000 Invention 49 3.5%MMA 50 Na-50 Mg 4600 800 7000 1100 5200 850 −15.5 13.5% AA 83.0% methoxyPEGM 2000 AA = Acrylic acid. MAA = Methacrylic acid. Methoxy PEGM 2000 =Methoxy polyethylene glycol with molecular weight 2000.

A reading of Tables 5a and 5b shows that the use of a copolymeraccording to the invention, totally acid or partially or totallyneutralised with one or more neutralisation agents having a monovalentneutralising function or a polyvalent neutralising function results inthe obtaining of aqueous suspensions of mineral pigments and/or fillers,according to the invention, with a high mineral matter content, stableover time and having a low Zeta potential.

EXAMPLE 6

This example relates to the grinding of a suspension of natural calciumcarbonate in order to refine into a microparticular suspension.

For this purpose, for each test, 0.75% by dry weight, with respect tothe total dry weight of the calcium carbonate, of grinding aid agent tobe tested, was introduced into an aqueous suspension of 42% dry matterof a marble coming from the Carrara deposits and with a mean diameter ofaround 10 μm.

The suspension circulated in a grinder of the Dyno-Mill type with afixed cylinder and rotating impeller, whose grinding substance consistedof corundum balls with a diameter in the range from 0.6 millimetres to 1millimetre.

The total volume occupied by the grinding substance was 1150 cubiccentimetres whilst its weight was 2900 g.

The grinding chamber had a volume of 1400 cubic centimetres.

The circumferential speed of the grinder was 10 metres per second.

The suspension of calcium carbonate was recycled at the rate of 18litres per hour.

The outlet of the Dyno-Mill was provided with a separator with 200micron mesh for separating the suspension resulting from the grindingand the grinding substance.

The temperature during each grinding test was kept at approximately 60°C.

At the end of the grinding (T₀), a sample of the pigmentary solution wasrecovered in a flask. The granulometry of the suspension (% of particlesless than 1 micrometre) was measured by means of a Sedigraph™ 5100granulometer from Micromeritics.

The Brookfield™ viscosity of the suspension was measured by means of aBrookfield™ type RVT viscometer, at a temperature of 20° C. and speedsof rotation of 10 revolutions per minute and 100 revolutions per minutewith the appropriate spindle.

After leaving at rest for 8 days in the flask, the Brookfield™ viscosityof the suspension was measured by introducing, into the unstirred flask,the appropriate spindle of the Brookfield™ type RVT viscometer, at atemperature of 20° C. and speeds of rotation of 10 revolutions perminute and 100 revolutions per minute (viscosity BS=before stirring).

The same Brookfield™ viscosity measurements were also carried out oncethe flask was stirred and constituted the AS (after stirring) viscosityresults.

Thus, in the different tests the following different grinding aid agentswere tested.

Test N^(o) 50:

This test, illustrating the invention, uses a polymer 100% neutralisedwith soda, with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 51:

This test, illustrating the invention, uses a polymer fully neutralisedwith potash, with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 52:

This test, illustrating the invention, uses a polymer, with a specificviscosity of 0.98, fully neutralised so that 50% of the acid groups areneutralised with soda and 50% of the acid groups are neutralised withmagnesium hydroxide, and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 53:

This test, illustrating the invention, uses a non-neutralised polymer,with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

All the Brookfield™ viscosity and Zeta potential experimental resultsmeasured with the same equipment and under the same operating conditionsas in Example 1 are set out in Table 6 below.

TABLE 6 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERDEGREE OF GRANU- INITIAL STIRRING STIRRING ZETA TEST CONSTITUENTNEUTRALISA- LOMETRY 10 100 10 100 10 100 POTENTIAL N° MONOMERS TION/ION(% <1 μm) rev/min rev/min rev/min rev/min rev/min rev/min (mV) Invention50 3.4% MMA 100 Na 70.4 2400 370 1700 455 750 170 −15.7 13.6% AA 83.0%methoxy PEGM 2000 Invention 51 3.4% MMA 100 K 73.9 2550 430 1500 535 950230 −13.4 13.6% AA 83.0% methoxy PEGM 2000 Invention 52 3.4% MMA 50Na-50 Mg 72.3 1300 300  650 120 650 112 −11.9 13.6% AA 83.0% methoxyPEGM 2000 Invention 53 3.4% MMA 0 70.7 2850 460 1350 315 500  93 −8.713.6% AA 83.0% methoxy PEGM 2000 AA = Acrylic acid. MAA = Methacrylicacid. Methoxy PEGM 2000 = Methoxy polyethylene glycol with molecularweight 2000.

A reading of Table 6 shows that the use of a copolymer according to theinvention, totally acidic or partially or totally neutralised with oneor more neutralisation agents having a monovalent neutralisationfunction or a polyvalent neutralisation function results in theobtaining of aqueous solutions of ground mineral pigments and/orfillers, according to the invention, with a moderate to high mineralmaterial content, stable over time and having a low Zeta potential.

EXAMPLE 7

This example relates to the grinding of a suspension of dolomite inorder to refine it into a microparticular suspension.

For this purpose, for each test, a grinding aid agent to be tested wasintroduced, to the extent of 0.5% by dry weight, with respect to thetotal dry weight of dolomite, into an aqueous suspension with 65% drymatter of a dolomite whose 4.2% are not passing through a 100 μm sieveand whose median diameter measured by means of a CILAS type 850granulometer was 15.03 micrometres.

The suspension circulated in a grinder of the Dyno-Mill type with fixedcylinder and rotating impeller, whose grinding substance consisted ofballs of corundum with a diameter in the range 0.6 millimetres to 1millimetre.

The total volume occupied by the grinding substance was 1150 cubiccentimetres whilst its weight was 2900 g.

The grinding chamber had a volume of 1400 cubic centimetres.

The circumferential speed of the grinder was 10 metres per second.

The suspension of dolomite was recycled at 18 litres per hour.

The outlet from the Dyno-Mill was provided with a separator with meshesof 200 microns for separating the suspension resulting from thegrinding, and the grinding substance.

The temperature during each grinding test was maintained atapproximately 60° C.

At the end of grinding (T₀), a sample of the pigmentary suspension wasrecovered in a flask. The granulometry of the suspension (% of particlesless than 2 micrometres) was measured by means of a CILAS type 850granulometer.

The Brookfield™ viscosity of the suspension was measured by means of aBrookfield™ type RVT viscometer, at a temperature of 20° C. and speedsof rotation of 10 revolutions per minute and 100 revolutions per minutewith the appropriate spindle.

After a residence time of 8 days in the flask, the Brookfield™ viscosityof the suspension was measured by introducing, into the unstirred flask,the appropriate spindle of the Brookfield™ type RVT viscometer, at atemperature of 20° C. and speeds of rotation of 10 revolutions perminute and 100 revolutions per minute (viscosity BS=before stirring).

The same Brookfield™ viscosity measurements were also made once theflask had been stirred and constitute the AS (after stirring) viscosityresults.

Thus, in the different tests, the following different grinding aidagents were tested.

Test N^(o) 54:

This test, illustrating the invention, uses a non-neutralised polymer,with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 55:

This test, illustrating the invention, uses a polymer fully neutralisedwith soda, with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 56:

This test, illustrating the invention, uses a polymer fully neutralisedwith potash, with a specific viscosity of 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

All the Brookfield™ viscosity and Zeta potential experimental resultsmeasured with the same equipment and under the same operating conditionsas in Example 1 are set out in Table 7 below.

TABLE 7 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERDEGREE OF GRANU- INITIAL STIRRING STIRRING ZETA TEST CONSTITUENTNEUTRALISA- LOMETRY 10 100 10 100 10 100 POTENTIAL N° MONOMERS TION/ION(% <2 μm) rev/min rev/min rev/min rev/min rev/min rev/min (mV) Invention54 3.4% MMA 0 50.4 1070 183 1940 274 1330 205 −5.7 13.6% AA 83.0%methoxy PEGM 2000 Invention 55 3.4% MMA 100 Na 56.6 2070 266 2300 3051910 261 −7.0 13.6% AA 83.0% methoxy PEGM 2000 Invention 56 3.4% MMA 100K 52.1 2570 341 3470 436 3460 439 −8.2 13.6% AA 83.0% methoxy PEGM 2000MAA = Methacrylic acid. AA = Acrylic acid. Methoxy PEGM 2000 = Methoxypolyethylene glycol with molecular weight 2000.

A reading of Table 7 shows that the use of a copolymer according to theinvention results in the obtaining of aqueous suspensions of grounddolomites, according to the invention, with a moderate to high mineralmaterial content, stable over time and having a low Zeta potential.

EXAMPLE 8

This example relates to the grinding of a suspension of natural calciumcarbonate in order to refine it into a microparticular suspension in anindustrial microelement grinder, followed by a reconcentration and adispersal of the concentrated suspension by means of the dispersingagent according to the invention.

For this purpose, for each test according to the invention (Tests 57 and58), after a grinding of an aqueous suspension with 41% dry matter of aNorwegian marble, using 0.6% by dry weight, with respect to the totaldry weight of the calcium carbonate, of a grinding aid agent accordingto the invention, a polymer neutralised to the extent of 50% molar bypotash, with a specific viscosity equal to 0.98 and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45,

a thermal reconcentration of the refined suspension obtained was carriedout until a slurry was obtained with a dry calcium carbonateconcentration of 72%.

For Test N^(o) 57 illustrating the invention, there was introduced intothe thermal concentrator, during the reconcentration step, 0.75% by dryweight, with respect to the dry weight of calcium carbonate, of thecopolymer fully neutralised with soda, with a specific viscosity of 0.98and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

For Test N^(o) 58 illustrating the invention, there was introduced intothe thermal concentrator, during the reconcentration step, 0.75% by dryweight, with respect to the dry weight of calcium carbonate, of thecopolymer with a specific viscosity of 0.98, fully neutralised withpotash and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

All the Brookfield™ viscosity, Zeta potential and granulometryexperimental results measured with the same equipment and under the sameoperating conditions as in Example 1 are set out in Table 8 below.

TABLE 8 DISPERSANT USED IN BROOKFIELD ™ VISCOSITY (mPa · s)RECONCENTRATION 8 days BEFORE 8 days AFTER DEGREE OF GRANU- INITIALSTIRRING STIRRING ZETA TEST CONSTITUENT NEUTRALISA- LOMETRY 10 100 10100 10 100 POTENTIAL N° MONOMERS TION/ION (% <1 μm) rev/min rev/minrev/min rev/min rev/min rev/min (mV) Invention 57 3.4% MMA 100 Na 76.62520 942 1100 900 1650 565 −7.2 13.6% AA 83.0% methoxy PEGM 2000Invention 58 3.4% MMA 100 K 75.7 1750 583 1200 690 1320 407 −7.8 13.6%AA 83.0% methoxy PEGM 200 AA = Acrylic acid. MAA = Methacrylic acid.Methoxy PEGM 2000 = Methoxy polyethylene glycol with molecular weight2000.

A reading of Table 8 shows that the use of a copolymer according to theinvention results in the obtaining of aqueous suspensions of mineralpigments and/or fillers ground and then reconcentrated, according to theinvention, with a moderate to high mineral material content, stable overtime and having a low Zeta potential.

EXAMPLE 9

This example relates to the preparation of a suspension of differentmineral fillers by simple dispersion and the revealing of the propertiesafforded by the presence of at least one monomer of formula (I) in thenon-ionic monomer.

For this purpose, the aqueous suspension of mineral filler to be testedis prepared by the introduction first of all of the agent to be testedinto the water and then of the mineral material to be dispersed.

Test N^(o) 59:

This test illustrates the invention and uses kaolin (kaolin SPS fromECC) as a mineral material at a dry matter concentration of 60.5% and,as a dispersing agent, 1.0% by dry weight, with respect to the dryweight of kaolin, of a copolymer with a specific viscosity of 0.98,fully neutralised with potash and consisting of:

a) 3.4% by weight methacrylic acid and 13.6% by weight acrylic acid asanionic monomers with a monocarboxylic function

b) 83.0% by weight of a monomer of formula (I) in which

-   -   R₁ represents hydrogen    -   R₂ represents hydrogen    -   R represents the methacrylate group    -   R′ represents the methyl radical

with (m+n+p)q=45.

Test N^(o) 60:

This test illustrates the invention and uses, as a mineral material,titanium dioxide sold by Tioxide under the name R-HD2 at a dry matterconcentration of 60.4% and, as a dispersing agent, 0.4% in dry weight,with respect to the dry weight of titanium dioxide, of the samecopolymer as the one used in Test N^(o) 59.

Test N^(o) 61:

This test illustrates the invention and uses, as a mineral material,lime supplied by Aldrich at a dry matter concentration of 60.6% and, asa dispersing agent, 1.0% by dry weight, with respect to the dry weightof lime, of the same copolymer as the one used in Test N^(o) 59.

Test N^(o) 62:

This test illustrates the invention and uses, as a mineral material,magnesium hydroxide supplied by Aldrich at a dry matter concentration of60.5% and, as a dispersing agent, 0.4% by dry weight, with respect tothe dry weight of magnesium hydroxide, of the same copolymer as the oneused in Test N^(o) 59.

Test N^(o) 63:

This test illustrates the invention and uses, as a mineral material, achalk sold by Omya under the name Etiquette Violette at a dry matterconcentration of 70% and, as a dispersing agent, 0.3% by dry weight,with respect to the dry weight of chalk, of the same copolymer as theone used in Test N^(o) 59.

All the Brookfield™ viscosity and Zeta potential experimental resultsmeasured with the same equipment and under the same operating conditionsas in Example 1 are set out in Table 9 below.

TABLE 9 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING ZETA TEST DRY 10 100 10 100 10 100 POTENTIALN° MINERAL FILLER MATTER % rev/min rev/min rev/min rev/min rev/minrev/min (mV) Invention 59 Kaolin 60.5 3830  760 8000 1400 5200 950 −10.6Invention 60 Titanium dioxide 60.4 2600  480 3000  550 1100 170 −17.2Invention 61 Chalk 60.6 800 530 20000  4800 10000  4400  −7.6 Invention62 Magnesium 60.5 400 180 3000 3800  200 130 −3.6 hydroxide Invention 63Chalk 70 790 146 3880  891 1740 277 −28

A reading of Table 9 shows that the use of a copolymer according to theinvention containing, as a non-ionic monomer, at least one monomer offormula (I) results in the obtaining of aqueous suspensions of mineralpigments and/or fillers, according to the invention, with a moderate tohigh mineral material content, stable over time and having a low Zetapotential, whatever the mineral material used.

EXAMPLE 10

The purpose of this example is to illustrate the low sensitivity of theaqueous suspensions according to the invention to alkaline pHs.

To do this, a quantity of polymer to be tested corresponding to 0.73% bydry weight with respect to the dry weight of mineral material wasintroduced into water.

After homogenisation of the polymer in the water by stirring, the pH ofthe medium was adjusted to 9 by adding soda.

The pH being constant, the necessary quantity of mineral material forobtaining a dry matter concentration of 70% was then introduced.

After 30 minutes stirring, ammonium hydroxide was added until a pH of 10was obtained.

The sample was then divided into three parts.

The first part was reserved for a study of the Brookfield™ viscositycarried out with the same operating method and the same equipment as inthe previous examples.

The second part of the sample was stirred for 30 minutes. After these 30minutes of stirring, the pH was lowered to 7.5 by means of acetic acid.

At the end of 20 minutes additional stirring, a measurement ofconductivity of the aqueous suspension of mineral material was carriedout by means of a conductivity meter type LF 320 sold byWissenschaftliche Technische Werkstätten. This value then correspondedto the conductivity of the suspension at a pH of 7.5. The sample wasthen subjected to a study of Brookfield™ viscosity as previouslydescribed.

The third part of the sample was stirred for 30 minutes. After these 30minutes of stirring, the pH was raised to 13 by adding soda.

At the end of 20 minutes additional stirring, a measurement ofconductivity of the aqueous suspension of mineral material was carriedout using the same conductivity meter as the one used previously. Thisvalue then corresponded to the conductivity of the suspension at a pH of13. The sample was then subjected to a study of Brookfield™ viscosity aspreviously described.

Test N^(o) 64:

This test illustrates the prior art and uses, as a mineral material, aprecipitated calcium carbonate sold by Solvay under the name Socal™ P3and, as a dispersing agent, a polyacrylic acid with a specific viscosityof 0.84.

Test N^(o) 65:

This test illustrates the invention and uses, as a mineral material, aprecipitated calcium carbonate sold by Solvay under the name Socal™ P3and, as a dispersing agent, the same copolymer as the one used in TestN^(o) 59.

All the Brookfield™ viscosity and conductivity experimental results areset out in Table 10 below.

TABLE 10 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING TEST 10 100 10 100 10 100 N° pH CONDUCTIVITYmS/cm rev/min rev/min rev/min rev/min rev/min rev/min Prior art 64 7.52.27 10000  2764 Viscosity too not measurable high 10 2.7 3460  926 3480991 3390 858 13 11.2 50800  7440 Viscosity too not measurable highInvention 65 7.5 1.4  320  252 1020 442  430 300 10 1.7  400  362  820531  450 366 13 4.8 8920 2500 10500  4230  8600 3204 

A reading of Table 10 shows that the use of a copolymer according to theinvention containing at least one monomer of formula (I) as a non-ionicmonomer results in the obtaining of aqueous suspensions of mineralpigments and/or fillers, according to the invention, with a moderate orhigh mineral matter content, stable over time and having a lowsensitivity to alkaline pHs.

EXAMPLE 11

The purpose of this example is to illustrate the low sensitivity of theaqueous suspensions according to the invention to acidic or weaklyalkaline pHs.

To do this, a quantity of polymer to be tested corresponding to 0.45% bydry weight with respect to the dry weight of mineral material wasintroduced into water.

After homogenisation of the polymer in water by stirring, the necessaryquantity of mineral material for obtaining a dry matter concentration of60% was introduced.

After 30 minutes stirring, the sample was then divided into three partsfor measurements of Brookfield™ viscosity and conductivity on each ofthe parts of the sample with the same operating method and the sameequipment as used in the previous example.

The first part corresponded to a natural pH of a dispersion of 8 and wasreserved for the study of Brookfield™ viscosity as described in Example10.

For the second part of the sample, the pH was reduced to 6 by means ofhydrochloric acid.

At the end of 20 minutes additional stirring, a measurement ofconductivity of the aqueous suspension of the mineral matter was carriedout. This value then corresponded to the conductivity of the suspensionfor a pH of 6.0. The sample was then subjected to a study of Brookfield™viscosity as previously described.

For the third part of the sample, the pH was reduced to 3 by a furtheraddition of hydrochloric acid.

At the end of 20 minutes additional stirring, a measurement ofconductivity of the aqueous suspension of mineral matter was carried outusing the same conductivity meter as the one used previously. This valuethen corresponded to the conductivity of the suspension at a pH of 3.This sample was then subjected to a study of Brookfield™ viscosity aspreviously described.

Test N^(o) 66:

This test illustrates the prior art and uses, as a mineral material, atitanium dioxide sold by Tioxide under the name R-HD2 and, as adispersing agent, a copolymer sold by Coatex under the name Coatex BR3,with a specific viscosity of 1.3.

In this test, it was impossible to continue the dispersion when the pHhad dropped to 3 since the titanium oxide had caked and blocked thedisperser.

The measurements of Brookfield™ viscosity and conductivity couldtherefore not be carried out at this pH value.

Test N^(o) 67:

This test illustrates the invention and uses, as a mineral matter, atitanium dioxide sold by Tioxide under the name R-HD2 and, as adispersing agent, the same copolymer as that used in Test N^(o) 59.

All the Brookfield™ viscosity and conductivity experimental results areset out in Table 11 below.

TABLE 11 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING TEST FINAL DRY CONDUCTIVITY 10 100 10 100 10100 N° pH EXTRACT (%) Ms/cm rev/min rev/min rev/min rev/min rev/minrev/min Prior art 66 3 Dispersion Dispersion Dispersion DispersionDispersion Dispersion Dispersion Dispersion BR 3 impossible impossibleimpossible impossible impossible impossible impossible impossible 6 59.52 24040  2592  Viscosity too high not measur- able 8 59.1 1.9  214 160302 218 165  98 Invention 67 3 59.9 4.84  79 136  95 148  89 102 6 58.91.25 3120 374 3400  336 3240  436 8 59.3 0.88  760 138 860 138 660 104

A reading of Table 11 shows that the use of a copolymer according to theinvention containing, as a non-ionic monomer, at least one monomer offormula (I) results in the obtaining of aqueous suspensions of mineralpigments and/or fillers, according to the invention, with a moderate tohigh mineral matter content, stable over time and having a lowsensitivity to changes from the natural pH of the dispersion to acid tohighly acid pHs.

EXAMPLE 12

The purpose of this example is to illustrate the low sensitivity toionic strength of the aqueous suspensions according to the invention.

To do this, with the same operating method and with the same equipmentas before, the mineral materials are put in suspension at a dry matterconcentration of 72% in salt water with a sodium chloride content of 2moles per litre of bipermuted water.

Test N^(o) 68:

This test illustrates the prior art and uses, as a mineral material, aprecipitated calcium carbonate sold by Solvay under the name Socal™ P3and, as a dispersing agent, 0.73% by dry weight, with respect to the dryweight of precipitated calcium carbonate, a polyacrylic acid with aspecific viscosity of 0.84.

It was impossible to put all the precipitated calcium carbonate insuspension, the spindle of the stirrer being locked before the end ofthe introduction of the total quantity of precipitated calciumcarbonate.

Test N^(o) 69:

This test illustrates the invention and uses, as a mineral material, aprecipitated calcium carbonate (sold by Solvay under the name Socal™ P3)and, as a dispersing agent, 0.73% by dry weight, with respect to the dryweight of precipitated calcium carbonate, the same copolymer as the oneused in Test N^(o) 53.

It was possible to put all the precipitated calcium carbonate insuspension and the Brookfield™ viscosity and conductivity experimentalresults are set out in Table 12 below.

TABLE 12 BROOKFIELD ™ VISCOSITY (mPa · s) 8 days BEFORE 8 days AFTERINITIAL STIRRING STIRRING TEST CONDUCTIVITY 10 100 10 100 10 100 N° pHmS/cm rev/min rev/min rev/min rev/min rev/min rev/min Prior 68 9Impossible to put all the calcium carbonate in suspension art Invention69 9 43.8 590 446 1000 960 620 544

A reading of Table 12 shows that the use of a copolymer according to theinvention containing, as a non-ionic monomer, at least one monomer offormula (I) results in the obtaining of aqueous suspensions of mineralpigments and/or fillers, according to the invention, with a moderate tohigh mineral matter content, stable over time and having a lowsensitivity to the ionic strength of the medium, thus making it possibleto obtain aqueous suspensions of mineral pigments and/or fillers whichcan be used in the field of drilling muds, in particular saturated saltmuds and sea water muds.

EXAMPLE 13

This example relates to the use of the dispersing agent, copolymeraccording to the invention in the field of paint and more particularlywater-based glazed paint. To do that, two tests are carried out.

-   -   Test n^(o) 70, which illustrates the prior art, uses the        dispersing agent COATEX BR 3    -   Test n^(o) 71, which illustrates the invention, uses the 100%        potash neutralised polymer of test n^(o) 42.

For the test n^(o) 70 illustrating the prior art, the constituents ofthe said water-based glazed paint were added in succession, these being:

40 g of monopropylene glycol

64 g of water

5 g of dispersing agent COATEX BR 3 at 40% solid content

2 g of a biocide, marketed by TROY under the name of MERGAL™ K6N

1 g of an anti-foaming agent marketed by HENKEL under the name of NOPCO™NDW

150 g of a calcium carbonate marketed by OMYA under the name of OMYA DP80 OG

200 g of titanium dioxide marketed by MILLENNIUM under the name RHD2

These constituents are stirred during 20 minutes, and then, the otherconstituents are added in succession, these being:

450 g of a styrene-acrylic binder in dispersion, marketed by RHODIAunder the name of RHODOPAS™ DS 910

30 g of butyldiglycol

100 g of water

4 g of a thickening agent marketed by COATEX under the name COATEXBR100P

1 g of 28% ammonia and

3 g of NOPCO™ NDW

After agitating the aqueous composition made up in this way for a fewminutes at a pH equal to 8.7 and after observing a good slurrying, theBrookfield™ viscosities of the different compositions are measured at25° C. and at 10 revolutions per minute and 100 revolutions per minuteusing a standard RVT Brookfield™ viscometer fitted with the requisitespindle. They are equal to 3400 mPa·s at 10 rpm and to 1900 mPa·s at 100rpm.

The ICI viscosity, which is a high shear (10 000 s⁻¹) viscosity, ismeasured with the use of a plan cone viscometer.

We obtain a ICI viscosity of 1.5.

The Stormer (KU) viscosity is also measured in Krebs Unit with the useof a Stormer viscometer.

We obtain a Stormer viscosity of 94 KU.

Test N^(o) 71:

For this test illustrating the invention, the constituents of thewater-based glazed, paint are added in succession, these being:

40 g of monopropylene glycol

62.7 g of water

6.3 g of the polymer of the test n^(o) 42 at a solid content of 31.6%

2 g of a biocide, marketed by TROY under the name of MERGAL™ K6N

1 g of an anti-foaming agent marketed by HENKEL under the name of NOPCO™NDW

150 g of a calcium carbonate marketed by OMYA under the name of OMYA DP80 OG

200 g of titanium dioxide marketed by MILLENNIUM under the name RHD2

These constituents are stirred during 20 minutes and then, the otherconstituents are added in succession, these being:

450 g of a styrene-acrylic binder in dispersion, marketed by RHODIAunder the name of RHODOPAS™ DS 910

30 g of butyldiglycol

100 g of water

4 g of a thickening agent marketed by COATEX under the name COATEXBR1002

1 g of 28% ammonia and

3 g of NOPCO™ NDW

After agitating the aqueous composition made up in this way for a fewminutes at a pH equal to 8.7 and after observing a good slurrying, theBrookfield™ viscosities of the different compositions are measured at25° C. and at 10 revolutions per minute and 100 revolutions per minuteusing a standard RVT Brookfield™ viscometer fitted with the requisitespindle. They are equal to 3000 mPa·s at 10 revolutions per minute and1700 mPa·s at 100 revolutions per minute.

The ICI viscosity, which is a high shear (10 000 S⁻¹) viscosity, ismeasured with the use of a plan cone viscometer.

We obtain a ICI viscosity of 1.4.

The Stormer (KU) viscosity is also measured in Krebs Unit with the useof a Stormer viscometer.

We obtain a Stormer viscosity of 93 KU.

The comparison between the obtained values for the use of the copolymeraccording to the invention and the obtained values for the use of apolymer, usually used by the skilled man in the art, allows to note thatthe copolymer according to the invention can be used in the field ofpaints.

EXAMPLE 14

This example concerns the use of the dispersing agent, the copolymeraccording to the invention, in the field of plastics materials.

For this purpose, an aqueous suspension of calcium carbonate (marble)obtained after flocculation was filtered in order to end up with amarble filtration cake with a mean diameter of 2 micrometres measured bymeans of a Sedigraph™ 5100.

From this cake, the aqueous suspension of marble was prepared byintroducing into the cake the required quantity by dry weight of thepolymer agent of Test N^(o) 4 according to the invention with respect tothe dry weight of the said cake to be put in suspension in order toobtain an aqueous suspension of marble at a dry matter concentration of68%.

Once this suspension had been produced, it was dried at a temperature ofless than 105° C. by the use of a laboratory dryer of the Niro™ type.

The powder obtained without any agglomerate was then divided into twosamples, one of which was to be the subject of the dispersion test in athermoplastic resin and the other the subject of the dispersion test ina thermosetting resin.

Test N^(o) 72:

This test, illustrating the invention, represents the test on thedispersion of the marble powder, previously obtained, in a thermoplasticresin.

For this purpose, 300 grams of previously prepared marble in powder formwith a mean diameter of 2 μm was introduced into a Z-arm Guittard mixerwith a capacity of 1.5 litres and having a vessel electrically heated to240° C.

After 15 minutes of preliminary heating of the load at 240° C., 3 gramsof commercial available zinc stearate and 125.5 grams of polypropylenehomopolymer sold by the company Appryl under the name PPH 3120MN1 wereintroduced.

The whole was mixed for 20 minutes at this temperature and at a speed of42 revolutions/minute.

With the mixture thus prepared, a calendering of part of this mixturewas then carried out in the form of sheets which were cut into smallcubes 2 to 3 millimetres square and whose MFI fluidity index wasmeasured at 230° C. under a load of 2.16 kg and 10 kg with a 2.09 mmdiameter die.

The MFI obtained was 8.0 g/10 min (230° C.-2.16 kg-2.09 mm) and 132 g/10min (230° C.-10 kg-2.09 mm).

This MFI result shows that the use of the agent, the copolymer accordingto the invention, results in loaded thermoplastic compositions which canbe used in the field of thermoplastics.

Test N^(o) 73:

This test, illustrating the invention, represents the test for thedispersion of marble powder, previously obtained, in a thermosettingresin of the unsaturated polyester type.

For this purpose, in a 500 ml metallic box, 90 grams of unsaturatedpolyester resin reference Palapreg P18 from BASF, 60 grams of anadditive called “Low Profile” and available under the reference LP40Afrom Union Carbide and 300 grams of the marble powder obtained wereweighed.

After 24 hours of storing at rest, a presence of settling orsedimentation before homogenisation was noted.

Homogenisation of the mixture by stirring with a spatula was thencarried out, and then the Brookfield™ viscosity at 100 revolutions/minwas measured after this 24 hours by means of a Brookfield™ type RVTviscometer equipped with the module 7.

It was 32,000 mPa·s.

It should be noted that this premixing of the polyester and calciumcarbonate can be used for manufacturing preimpregnates of the SMC (SheetMoulding Compound) or BMC (Bulk Moulding Compound) type.

EXAMPLE 15

This example concerns the use of an aqueous suspension of mineralfillers according to the invention in the field of paper. It relatesmore specifically to the determination of the different Brookfield™viscosity and water retention values of the different 100% calciumcarbonate coating colors.

Test N^(o) 74:

This test illustrates the prior art and uses a coating color composedof:

-   -   100 parts, expressed as dry matter, of an aqueous suspension        according to the prior art, at 72% by dry weight of calcium        carbonate having a particle such as 75% of the particles have a        diameter less than 1 μm determined by Sedigraph™ 5100 and having        0-75% by dry weight of a dispersing agent marketed by Coatex        under the name M 777,    -   12 parts, expressed as dry matter, of a styrene-butadiene latex        sold by Dow under the name “DL 950”,    -   0.5 parts, expressed as dry matter, of a water retention agent        marketed by Coatex under the name Rheocoat™ 35.

The solid content of the coating color is about 65%.

Test N^(o) 75:

This test illustrates the invention and uses a coating color composedof:

-   -   100 parts, expressed as dry matter, of an aqueous suspension        according to the invention, at 72% by dry weight of calcium        carbonate having a particle such as 75% of the particles have a        diameter less than 1 μm determined by Sedigraph™ 5100 and having        0-75% by dry weight of a dispersing agent according to the        invention and composed of 20% by weight of acrylic acid; 80% of        methoxy PEG 2000 methacrylate having a specific viscosity of        1.26,    -   12 parts, expressed as dry matter, of a styrene-butadiene latex        sold by Dow under the name “DL 950”,    -   0.5 parts, expressed as dry matter, of a water retention agent        marketed by Coatex under the name Rheocoat™ 35.

The solid content of the coating color is about 65%.

The results of the measurements of Brookfield™ viscosity determined at10 and 100 revolutions per minute at 25° C. by means of a Brookfield™viscometer type DV-1 equipped with the appropriate spindle are:

For test n^(o) 74 according to the prior art: Brookfield™ viscosity at10 rpm=8000 mPa·s Brookfield™ viscosity at 100 rpm=1500 mPa·s

For test n^(o) 75 according to the invention. Brookfield™ viscosity at10 rpm=9200 mPa·s Brookfield™ viscosity at 100 rpm=1800 mPa·s

The results of the water retention measurements obtained according tothe following method is:

-   -   For test n^(o) 74 according to the prior art, the water volume        after 10 minutes is 3.2 ml,    -   For test n^(o) 75 according to the invention, the water volume        after 10 minutes is 2.8 ml.

So, in order to measure the water retentions, the paper coating color tobe tested is subjected to a pressure of 100 psi (7 bars) in a standardcylinder, equipped with a surface of the filter paper type capable ofallowing water to pass.

After 10 minutes, the volume of water collected is measured in ml.

The lower the volume of water collected at the end of 10 minutes, thebetter is the retention.

To do this, use is made of an “API Fluid Loss Measurement” filter pressfrom Baroid, which is composed essentially of a clamp provided with aclamping screw for locking the three parts of the filter body.

This body is composed of:

-   -   a base with a hole provided with a nozzle through which the        filtrate flows. This base supports a metallic sieve with a mesh        of 60 to 80, on which is placed the 90 mm diameter filter paper        (Whatman™ N^(o)50), the equivalent of which is the DURIEUX BLEU™        N^(o) 3 type,    -   a cylinder with an inside diameter of 76.2 mm and a height of        128 mm,    -   a cover provided with a compressed gas inlet, whose seal with        the cylinder is provided by means of a flat joint, of the same        type as those placed on the base.

To use the filter press, the following are fitted in the followingorder:

-   -   the joint on the base    -   the sieve on the joints    -   the filter paper on the sieve    -   the second joint on the filter paper

and the cylinder is fitted on the base before locking the bayonetsystem.

Then it is filled with the coating color to be tested (approximately 480g up to 3 cm from the top of the cylinder) before placing the cover onthe cylinder, interposing a joint.

Then the assembly is placed in the clamp and is locked by means of theclamping screw, and then a graduated tube is arranged underneath thenozzle.

A pressure of 7 bars is applied, simultaneously triggering achronometer.

After 20 minutes the volume of fluid collected in the test tube isnoted. The accuracy of the result obtained is ±0.2 ml.

The reading of the previous results shows that the characteristics ofthe rheology and of the water-retention concerning the test according tothe invention allow to use the aqueous suspensions according to theinvention in the field of paper and more particularly in the coating ofpaper.

1. A process comprising: at least one of dispersing or grinding amineral pigment, filler or combination thereof, in aqueous suspension inthe presence of a water-soluble copolymer, wherein said water-solublecopolymer comprises polymerized units of a) at least one anionic monomerwith an unsaturated ethylenic chain and a monocarboxylic function, b)optionally, at least one anionic monomer with an unsaturated ethylenicchain and a dicarboxylic, sulphonic, phosphoric, phosphonic function ora combination thereof, c) at least one non-ionic monomer having anunsaturated ethylenic chain of formula (I):

in which m and p represent a number of alkylene oxide units and are lessthan or equal to 150, n represents a number of ethylene oxide units andis less than or equal to 150, q represents a number at least equal to 1and5≦(m+n+p)q≦150 R₁ is hydrogen, methyl or ethyl radical, R₂ is hydrogen,methyl or ethyl radical, R is selected from the group consisting ofacrylurethane, methacrylurethane, α-α′-dimethylisopropenylbenzylurethane and allyl urethane, R′ represents a hydrocarbon radical having1 to 5 carbon atoms, d) optionally, an acrylamide monomer,methacrylamide monomer, a derivative thereof or a mixture thereof, orone or more non water-soluble monomers, and e) optionally, at least onemonomer having at least two unsaturated ethylenic chains selected fromthe group consisting of ethylene glycol dimethacrylate,trimethylolpropane-triacrylate, allyl acrylate, allyl maleate,methylenebisacrylamide, methylenebismethacrylamide, tetrallyloxyethane,a triallylcyanurate, and an allyl ether obtained from a polyol, whereinthe total of a), b), c), d) and e) is 100%, and wherein the copolymerhas a specific viscosity of no more than
 10. 2. The process of claim 1,wherein the copolymer comprises at least one monomer a) selected fromthe group consisting of acrylic acid, methacrylic acid, a diacidhemiester and mixtures thereof.
 3. The process of claim 1, wherein thecopolymer comprises at least one monomer a) selected from the groupconsisting of a C₁ to C₄ monoester of maleic acid, a C₁ to C₄ monoesterof itaconic acid and mixtures thereof.
 4. The process of claim 1,wherein the copolymer comprises at least one anionic monomer b) selectedfrom the group consisting of crotonic acid, isocrotonic acid, cinnamicacid, itaconic acid, maleic acid, citraconic acid, a carboxylic acidanhydride, maleic anhydride, acrylamido-methyl-propanesulphonic acid,sodium methallyl sulphonate, vinyl sulfonic acid, styrene sulphonicacid, vinyl phosphoric acid, ethylene glycol methacrylic phosphate,propylene glycol methacrylic phosphate, ethylene glycol acrylatephosphate, propylene glycol acrylate phosphate, ethoxylates thereof,phosphonic vinyl acid and mixtures thereof.
 5. The process of claim 1,wherein the copolymer comprises at least one monomer d) selected fromthe group consisting of an alkylacrylate, an alkyl methacrylate, a vinylcompound, vinyl acetate, vinylpyrrolidone, styrene, alphamethylstyrene,derivatives thereof and mixtures thereof.
 6. The process of claim 1,wherein the copolymer comprises at least one monomer e) obtained frompentaerythritol, sorbitol, sucrose or mixtures thereof.
 7. The processof claim 1, wherein the copolymer has a specific viscosity of no morethan
 5. 8. The process of claim 1, wherein the copolymer has a specificviscosity of no more than
 2. 9. The process of claim 1, wherein thecopolymer comprises monomer a) in an amount of from 2% to 85%, themonomer b) in an amount of from 0 to 80%, the monomer c) in an amount offrom 20 to 95%, the monomer d) in an amount of from 0 to 50%, and themonomer e) in an amount of from 0 to 3%.
 10. The process of claim 1,wherein the copolymer comprises monomer a) in an amount of from 2 to80%.
 11. The process of claim 1, wherein the copolymer comprises monomerb) in an amount of from 0 to 50%.
 12. The process of claim 1, whereinthe copolymer comprises monomer b) in an amount of from 0 to 20%. 13.The process of claim 1, wherein monomer a) is selected from the groupconsisting of acrylic and methacrylic acid, and monomer b) is selectedfrom the group consisting of itaconic acid, maleic acid,acrylamido-methyl-propane sulphonic acid, sodium methallylsulphonate,vinyl sulphonic acid, styrene sulphonic acid, ethylene glycolmethacrylate phosphate, propylene glycol methacrylate phosphate,ethylene glycol acrylate phosphate, propylene glycol acrylate phosphate,ethoxylates thereof and mixtures thereof.
 14. The process as claimed inclaim 1, comprising grinding.
 15. The process as claimed in claim 1,comprising dispersing.
 16. The process as claimed in claim 1, whereinthe copolymer is in acid form, is optionally distilled, and is partiallyneutralized, completely neutralized or combination thereof, by one ormore neutralization agents having a monovalent neutralizing function ora polyvalent neutralizing function.
 17. The process of claim 16, whereinthe copolymer is partially or completely neutralized by an alkalication, an aliphatic amine, a cyclic amine, a primary amine, a secondaryamine, a tertiary amine, an ethanolamine, an alkaline-earth divalentcation, a trivalent cation, a cation with higher valency or a mixturethereof.
 18. The process of claim 16, wherein the neutralizing agent isselected from the group consisting of a sodium cation, a potassiumcation, a lithium cation, an ammonium cation, stearylamine,monoethanolamine, diethanolamine, triethanolamine, monoethylamine,diethylamine, cyclohexylamine, methylcyclohexylamine, a magnesiumcation, a calcium cation, a zinc cation, an aluminum cation and amixture thereof.
 19. The process of claim 16, wherein the copolymer isobtained from a copolymerization reaction, and is treated and separatedinto a plurality of phases, before or after complete or partialneutralization, by treating with one or more polar solvents selectedfrom the group consisting of water, methanol, ethanol, propanol,isopropanol, butanol, acetone, tetrahydrofuran and mixtures thereof. 20.A dispersing and/or grinding agent comprising a copolymer comprisingpolymerized units of a) at least one anionic monomer with an unsaturatedethylenic chain and a monocarboxylic function, b) optionally, at leastone anionic monomer with an unsaturated ethylenic chain and adicarboxylic, sulphonic, phosphoric, phosphonic function or acombination thereof, c) at least one non-ionic monomer with anunsaturated ethylenic chain of formula (I):

in which m and p represent a number of alkylene oxide units and are lessthan or equal to 150, n represents a number of ethylene oxide units andis less than or equal to 150, q represents a number at least equal to 1and5≦(m+n+p)q≦150 R₁ is hydrogen, methyl or ethyl radical, R₂ is hydrogen,methyl or ethyl radical, R is selected from the group consisting ofacrylurethane, methacrylurethane, α-α′-dimethyl-isopropenylbenzylurethane and allyl urethane, R′ represents a hydrocarbon radical having1 to 5 carbon atoms, d) optionally, an acrylamide monomer,methacrylamide monomer, a derivative thereof or a mixture thereof, orone or more non water-soluble monomers, and e) optionally, at least onemonomer having at least two unsaturated ethylenic chains selected fromthe group consisting of ethylene glycol dimethacrylate,trimethylolpropane-triacrylate, allyl acrylate, an allyl maleate,methylenebisacrylamide, methylenebismethacrylamide, tetrallyloxyethane,a triallylcyanurate, and an allyl ether obtained from a polyol, whereinthe total of a), b), c), d) and e) is 100%, and wherein the copolymerhas a specific viscosity of no more than
 10. 21. The dispersing and/orgrinding agent of claim 20, wherein the copolymer comprises at least onemonomer a) selected from the group consisting of acrylic acid,methacrylic acid, a diacid hemiester and mixtures thereof.
 22. Thedispersing and/or grinding agent of claim 20, wherein the copolymercomprises at least one monomer a) selected from the group consisting ofa C₁ to C₄ monoester of maleic acid, a C₁ to C₄ monoester of itaconicacid and mixtures thereof.
 23. The dispersing and/or grinding agent ofclaim 20, wherein the copolymer comprises at least one anionic monomerb) selected from the group consisting of crotonic acid, isocrotonicacid, cinnamic acid, itaconic acid, maleic acid, citraconic acid, acarboxylic acid anhydride, maleic anhydride,acrylamido-methyl-propanesulphonic acid, sodium methallyl sulphonate,vinyl sulfonic acid, styrene sulphonic acid, vinyl phosphoric acid,ethylene glycol methacrylic phosphate, and phosphonic vinyl acid. 24.The dispersing and/or grinding agent of claim 20, wherein the copolymercomprises at least one monomer d) selected from the group consisting ofan alkylacrylate, an alkyl methacrylate, a vinyl compound, vinylacetate, vinylpyrrolidone, styrene, alphamethylstyrene, derivativesthereof and mixtures thereof.
 25. The dispersing and/or grinding agentof claim 20, wherein the copolymer comprises at least one monomer e)obtained from pentaerythritol, sorbitol, sucrose or mixtures thereof.26. The dispersing and/or grinding agent of claim 20, wherein thecopolymer has a specific viscosity of no more than
 5. 27. The dispersingand/or grinding agent of claim 20, wherein the copolymer has a specificviscosity of no more than
 2. 28. The dispersing and/or grinding agent ofclaim 20, wherein the copolymer comprises monomer a) in an amount offrom 2% to 85%, the monomer b) in an amount of from 0 to 80%, themonomer c) in an amount of from 20 to 95%, the monomer d) in an amountof from 0 to 50%, and the monomer e) in an amount of from 0 to 3%. 29.The dispersing and/or grinding agent of claim 20, wherein the copolymercomprises monomer a) in an amount of from 2 to 80%.
 30. The dispersingand/or grinding agent of claim 20, wherein the copolymer comprisesmonomer b) in an amount of from 0 to 50%.
 31. The dispersing and/orgrinding agent of claim 20, wherein the copolymer comprises monomer b)in an amount of from 0 to 20%.
 32. The dispersing and/or grinding agentof claim 20, wherein monomer a) is selected from the group consisting ofacrylic acid and methacrylic acid, and monomer b) is selected from thegroup consisting of itaconic acid, maleic acid,acrylamido-methyl-propane sulphonic acid, sodium methallylsulphonate,vinyl sulphonic acid, styrene sulphonic acid, ethylene glycolmethacrylate phosphate, propylene glycol methacrylate phosphate,ethylene glycol acrylate phosphate, propylene glycol acrylate phosphate,ethoxylates thereof and mixtures thereof.
 33. The dispersing and/orgrinding agent of claim 32, wherein the copolymer is obtained byneutralizing with a neutralizing agent having a monovalent or polyvalentneutralizing function, said neutralizing agent selected from the groupconsisting of an alkaline cation, an aliphatic amine, a cyclic amine, aprimary amine, a secondary amine, a tertiary amine, an ethanolamine, analkaline-earth divalent cation, a trivalent cation, a cation with highervalency or a mixture thereof.
 34. The dispersing and/or grinding agentof claim 32, wherein the copolymer is obtained by neutralizing with aneutralizing agent having a monovalent or polyvalent neutralizingfunction, said neutralizing agent selected from the group consisting ofa sodium cation, a potassium cation, a lithium cation, an ammoniumcation, stearylamine, monoethanolamine, diethanolamine, triethanolamine,monoethylamine, diethylamine, cyclohexylamine, methylcyclohexylamine, amagnesium cation, a calcium cation, a zinc cation, an aluminum cationand a mixture thereof.
 35. The dispersing and/or grinding agent of claim20, wherein the copolymer is obtained from a copolymerization reaction,and is treated and separated into a plurality of phases, before or aftercomplete or partial neutralization, by treating with one or more polarsolvents selected from the group consisting of water, methanol, ethanol,propanol, isopropanol, butanol, acetone, tetrahydrofuran and mixturesthereof.
 36. An aqueous suspension comprising at least one of a filleror pigment and the dispersing and/or grinding agent of claim 20, whereinthe dispersing and/or grinding agent is present in an amount of from0.05 to 5% by dry weight based on the dry weight of the fillers andpigments.
 37. The aqueous suspension of claim 36, wherein the dispersingagent is present in an amount of from 0.3 to 1.0% by dry weight.
 38. Theaqueous suspension as claimed in claim 36, wherein the fillers andpigments are selected from the group consisting of a natural calciumcarbonate, a calcite, a chalk, a marble, a synthetic calcium carbonate,a precipitated calcium carbonate, a dolomite, a magnesium hydroxide, akaolin, a talc, a gypsum, titanium dioxide, aluminum hydroxide and afiller or pigment used in the papermaking or petroleum field.
 39. Theaqueous suspension of claim 36 having a zeta potential of from 0 to −30mV.
 40. The aqueous suspension of claim 36, wherein the zeta potentialis from 0 to −20 mV.
 41. A process for manufacturing a sheet of paperwith a composition comprising the aqueous suspension of claim
 36. 42. Asheet of paper obtained by the process of claim
 41. 43. A processcomprising coating a sheet of paper with a composition comprising theaqueous suspension of claim
 36. 44. A sheet of paper obtained by theprocess of claim
 43. 45. A process comprising prospecting for orextracting petroleum, wherein the aqueous suspension of claim 36 isincorporated into a saturated salt mud or seawater mud.
 46. A drillingmud comprising the aqueous suspension of claim
 36. 47. A paintcomprising the dispersing and/or grinding agent of claim
 20. 48. Athermoplastic or thermosetting resin comprising the dispersing and/orgrinding agent of claim
 20. 49. A process comprising: at least one ofdispersing or grinding a mineral pigment, filler or combination thereof,in aqueous suspension in the presence of a water-soluble copolymer,wherein said water-soluble copolymer comprises polymerized units of a)at least one anionic monomer with an unsaturated ethylenic chain and amonocarboxylic function, b) optionally, at least one anionic monomerwith an unsaturated ethylenic chain and a dicarboxylic, sulphonic,phosphoric, phosphonic function or a combination thereof, c) at leastone non-ionic monomer having an unsaturated ethylenic chain of formula(I):

in which m and p represent a number of alkylene oxide units and are lessthan or equal to 150, n represents a number of ethylene oxide units andis less than or equal to 150, q represents a number at least equal to 1and5≦(m+n+p)q≦150 R₁ is hydrogen, methyl or ethyl radical, R₂ is hydrogen,methyl or ethyl radical, R is an acrylic ester, a methacrylic ester, amaleic ester, an itaconic ester, a crotonic ester, a vinyl phthalicester, an unsaturated urethane, an allyl ether, a vinyl ether or anethylenically unsaturated amide, R′ represents a hydrocarbon radicalhaving 1 to 5 carbon atoms, d) optionally, an acrylamide monomer,methacrylamide monomer, a derivative thereof or a mixture thereof, orone or more non water-soluble monomers, and e) at least one monomerhaving at least two unsaturated ethylenic chains selected from the groupconsisting of ethylene glycol dimethacrylate,trimethylolpropane-triacrylate, allyl acrylate, an allyl maleate,methylenebisacrylamide, methylenebismethacrylamide, tetrallyloxyethane,a triallylcyanurate, and an allyl ether obtained from a pentaerythritol,sorbitol, sucrose or mixtures thereof, wherein the total of a), b), c),d) and e) is 100%, and wherein the copolymer has a specific viscosity ofno more than
 10. 50. The process of claim 49, wherein the copolymercomprises at least one monomer a) selected from the group consisting ofacrylic acid, methacrylic acid, a diacid hemiester and mixtures thereof.51. The process of claim 49, wherein the copolymer comprises at leastone monomer a) selected from the group consisting of a C₁ to C₄monoester of maleic acid, a C₁ to C₄ monoester of itaconic acid andmixtures thereof.
 52. The process of claim 49, wherein the copolymercomprises at least one anionic monomer b) selected from the groupconsisting of crotonic acid, isocrotonic acid, cinnamic acid, itaconicacid, maleic acid, citraconic acid, a carboxylic acid anhydride, maleicanhydride, acrylamido-methyl-propanesulphonic acid, sodium methallylsulphonate, vinyl sulfonic acid, styrene sulphonic acid, vinylphosphoric acid, ethylene glycol methacrylic phosphate, propylene glycolmethacrylic phosphate, ethylene glycol acrylate phosphate, propyleneglycol acrylate phosphate, ethoxylates thereof, phosphonic vinyl acidand mixtures thereof.
 53. The process of claim 49, wherein the copolymercomprises at least one non-ionic monomer c) wherein R is selected fromthe group consisting of acrylurethane, methacrylurethane,α-α′-dimethylisopropenylbenzyl urethane and allyl urethane.
 54. Theprocess of claim 49, wherein the copolymer comprises at least onemonomer d) selected from the group consisting of an alkylacrylate, analkyl methacrylate, a vinyl compound, vinyl acetate, vinylpyrrolidone,styrene, alphamethylstyrene, derivatives thereof and mixtures thereof.55. The process of claim 49, wherein the copolymer has a specificviscosity of no more than
 5. 56. The process of claim 49, wherein thecopolymer has a specific viscosity of no more than
 2. 57. The process ofclaim 49, wherein the copolymer comprises monomer a) in an amount offrom 2% to 85%, the monomer b) in an amount of from 0 to 80%, themonomer c) in an amount of from 20 to 95%, the monomer d) in an amountof from 0 to 50%, and the monomer e) in an amount of from 0 to 3%. 58.The process of claim 49, wherein the copolymer comprises monomer a) inan amount of from 2 to 80%.
 59. The process of claim 49, wherein thecopolymer comprises monomer b) in an amount of from 0 to 50%.
 60. Theprocess of claim 49, wherein the copolymer comprises monomer b) in anamount of from 0 to 20%.
 61. The process of claim 49, wherein monomer a)is selected from the group consisting of acrylic and methacrylic acid,and monomer b) is selected from the group consisting of itaconic acid,maleic acid, acrylamido-methyl-propane sulphonic acid, sodiummethallylsulphonate, vinyl sulphonic acid, styrene sulphonic acid,ethylene glycol methacrylate phosphate, propylene glycol methacrylatephosphate, ethylene glycol acrylate phosphate, propylene glycol acrylatephosphate, ethoxylates thereof and mixtures thereof.
 62. The process asclaimed in claim 49, comprising grinding.
 63. The process as claimed inclaim 49, comprising dispersing.
 64. The process as claimed in claim 49,wherein the copolymer is in acid form, is optionally distilled, and ispartially neutralized, completely neutralized or combination thereof, byone or more neutralization agents having a monovalent neutralizingfunction or a polyvalent neutralizing function.
 65. The process of claim64, wherein the copolymer is partially or completely neutralized by analkali cation, an aliphatic amine, a cyclic amine, a primary amine, asecondary amine, a tertiary amine, an ethanolanine, an alkaline-earthdivalent cation, a trivalent cation, a cation with higher valency or amixture thereof.
 66. The process of claim 64, wherein the neutralizingagent is selected from the group consisting of a sodium cation, apotassium cation, a lithium cation, an ammonium cation, stearylamine,monoethanolamine, diethanolamine, triethanolamine, monoethylamine,diethylamine, cyclohexylamine, methylcyclohexylamine, a magnesiumcation, a calcium cation, a zinc cation, an aluminum cation and amixture thereof.
 67. The process of claim 64, wherein the copolymer isobtained from a copolymerization reaction, and is treated and separatedinto a plurality of phases, before or after complete or partialneutralization, by treating with one or more polar solvents selectedfrom the group consisting of water, methanol, ethanol, propanol,isopropanol, butanol, acetone, tetrahydrofuran and mixtures thereof. 68.A dispersing and/or grinding agent comprising a copolymer comprisingpolymerized units of a) at least one anionic monomer with an unsaturatedethylenic chain and a monocarboxylic function, b) optionally, at leastone anionic monomer with an unsaturated ethylenic chain and adicarboxylic, sulphonic, phosphoric, phosphonic function or acombination thereof, c) at least one non-ionic monomer with anunsaturated ethylenic chain of formula (I):

in which m and p represent a number of alkylene oxide units and are lessthan or equal to 150, n represents a number of ethylene oxide units andis less than or equal to 150, q represents a number at least equal to 1and5≦(m+n+p)q≦150 R₁ is hydrogen, methyl or ethyl radical, R₂ is hydrogen,methyl or ethyl radical, R is an acrylic ester, a methacrylic ester, amaleic ester, a itaconic ester, a crotonic ester, a vinyl phthalicester, an unsaturated urethane, an allyl ether, a vinyl ether or anethylenically unsaturated amide, R′ represents a hydrocarbon radicalhaving 1 to 5 carbon atoms, d) optionally, an acrylamide monomer,methacrylamide monomer, a derivative thereof or a mixture thereof, orone or more non water-soluble monomers, and e) at least one monomerhaving at least two unsaturated ethylenic chains selected from the groupconsisting of ethylene glycol dimethacrylate,trimethylolpropane-triacrylate, allyl acrylate, an allyl maleate,methylenebisacrylamide, methylenebismethacrylamide, tetrallyloxyethane,a triallylcyanurate, and an allyl ether obtained from a pentaerythritol,sorbitol, sucrose or mixtures thereof, wherein the total of a), b), c),d) and e) is 100%, and wherein the copolymer has a specific viscosity ofno more than
 10. 69. The dispersing and/or grinding agent of claim 68,wherein the copolymer comprises at least one monomer a) selected fromthe group consisting of acrylic acid, methacrylic acid, a diacidhemiester and mixtures thereof.
 70. The dispersing and/or grinding agentof claim 68, wherein the copolymer comprises at least one monomer a)selected from the group consisting of a C₁ to C₄ monoester of maleicacid, a C₁ to C₄ monoester of itaconic acid and mixtures thereof. 71.The dispersing and/or grinding agent of claim 68, wherein the copolymercomprises at least one anionic monomer b) selected from the groupconsisting of crotonic acid, isocrotonic acid, cinnamic acid, itaconicacid, maleic acid, citraconic acid, a carboxylic acid anhydride, maleicanhydride, acrylamido-methyl-propanesulphonic acid, sodium methallylsulphonate, vinyl sulfonic acid, styrene sulphonic acid, vinylphosphoric acid, ethylene glycol methacrylic phosphate, and phosphonicvinyl acid.
 72. The dispersing and/or grinding agent of claim 68,wherein the copolymer comprises at least one non-ionic monomer c)wherein R is selected from the group consisting of acrylurethane,methacrylurethane, α-α′-dimethyl-isopropenylbenzyl urethane and allylurethane.
 73. The dispersing and/or grinding agent of claim 68, whereinthe copolymer comprises at least one monomer d) selected from the groupconsisting of an alkylacrylate, an alkyl methacrylate, a vinyl compound,vinyl acetate, vinylpyrrolidone, styrene, alphamethylstyrene,derivatives thereof and mixtures thereof.
 74. The dispersing and/orgrinding agent of claim 68, wherein the copolymer has a specificviscosity of no more than
 5. 75. The dispersing and/or grinding agent ofclaim 68, wherein the copolymer has a specific viscosity of no more than2.
 76. The dispersing and/or grinding agent of claim 68, wherein thecopolymer comprises monomer a) in an amount of from 2% to 85%, themonomer b) in an amount of from 0 to 80%, the monomer c) in an amount offrom 20 to 95%, the monomer d) in an amount of from 0 to 50%, and themonomer e) in an amount of from 0 to 3%.
 77. The dispersing and/orgrinding agent of claim 68, wherein the copolymer comprises monomer a)in an amount of from 2 to 80%.
 78. The dispersing and/or grinding agentof claim 68, wherein the copolymer comprises monomer b) in an amount offrom 0 to 50%.
 79. The dispersing and/or grinding agent of claim 68,wherein the copolymer comprises monomer b) in an amount of from 0 to20%.
 80. The dispersing and/or grinding agent of claim 68, whereinmonomer a) is selected from the group consisting of acrylic acid andmethacrylic acid, and monomer b) is selected from the group consistingof itaconic acid, maleic acid, acrylamido-methyl-propane sulphonic acid,sodium methallylsulphonate, vinyl sulphonic acid, styrene sulphonicacid, ethylene glycol methacrylate phosphate, propylene glycolmethacrylate phosphate, ethylene glycol acrylate phosphate, propyleneglycol acrylate phosphate, ethoxylates thereof and mixtures thereof. 81.The dispersing and/or grinding agent of claim 80, wherein the copolymeris obtained by neutralizing with a neutralizing agent having amonovalent or polyvalent neutralizing function, said neutralizing agentselected from the group consisting of an alkaline cation, an aliphaticamine, a cyclic amine, a primary amine, a secondary amine, a tertiaryamine, an ethanolamine, an alkaline-earth divalent cation, a trivalentcation, a cation with higher valency or a mixture thereof.
 82. Thedispersing and/or grinding agent of claim 80, wherein the copolymer isobtained by neutralizing with a neutralizing agent having a monovalentor polyvalent neutralizing function, said neutralizing agent selectedfrom the group consisting of a sodium cation, a potassium cation, alithium cation, an ammonium cation, stearylamine, monoethanolamine,diethanolamine, triethanolamine, monoethylamine, diethylamine,cyclohexylamine, methylcyclohexylamine, a magnesium cation, a calciumcation, a zinc cation, an aluminum cation and a mixture thereof.
 83. Thedispersing and/or grinding agent of claim 68, wherein the copolymer isobtained from a copolymerization reaction, and is treated and separatedinto a plurality of phases, before or after complete or partialneutralization, by treating with one or more polar solvents selectedfrom the group consisting of water, methanol, ethanol, propanol,isopropanol, butanol, acetone, tetrahydrofuran and mixtures thereof. 84.An aqueous suspension comprising at least one of a filler or pigment andthe dispersing and/or grinding agent of claim 68, wherein the dispersingand/or grinding agent is present in an amount of from 0.05 to 5% by dryweight based on the dry weight of the fillers and pigments.
 85. Theaqueous suspension of claim 84, wherein the dispersing agent is presentin an amount of from 0.3 to 1.0% by dry weight.
 86. The aqueoussuspension as claimed in claim 84, wherein the fillers and pigments areselected from the group consisting of a natural calcium carbonate, acalcite, a chalk, a marble, a synthetic calcium carbonate, aprecipitated calcium carbonate, a dolomite, a magnesium hydroxide, akaolin, a talc, a gypsum, titanium dioxide, aluminum hydroxide and afiller or pigment used in the papermaking or petroleum field.
 87. Theaqueous suspension of claim 84, having a zeta potential of from 0 to −30mV.
 88. The aqueous suspension of claim 84, wherein the zeta potentialis from 0 to −20 mV.
 89. A process for manufacturing a sheet of paperwith a composition comprising the aqueous suspension of claim
 84. 90. Asheet of paper obtained by the process of claim
 89. 91. A processcomprising coating a sheet of paper with a composition comprising theaqueous suspension of claim
 84. 92. A sheet of paper obtained by theprocess of claim
 91. 93. A process comprising prospecting for orextracting petroleum, wherein the aqueous suspension of claim 84 isincorporated into a saturated salt mud or seawater mud.
 94. A drillingmud comprising the aqueous suspension of claim
 84. 95. A paintcomprising the dispersing and/or grinding agent of claim
 68. 96. Athermoplastic or thermosetting resin comprising the dispersing and/orgrinding agent of claim 68.